Expressions & Equations 2013-01-23

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  • Expressions & Equations www.njctl.org 2013-01-23
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  • Setting the PowerPoint View Use Normal View for the Interactive Elements To use the interactive elements in this presentation, do not select the Slide Show view. Instead, select Normal view and follow these steps to set the view as large as possible: On the View menu, select Normal. Close the Slides tab on the left. In the upper right corner next to the Help button, click the ^ to minimize the ribbon at the top of the screen. On the View menu, confirm that Ruler is deselected. On the View tab, click Fit to Window. On the View tab, click Slide Master | Page Setup. Select On-screen Show (4:3) under Slide sized for and click Close Master View. On the Slide Show menu, confirm that Resolution is set to 1024x768. Use Slide Show View to Administer Assessment Items To administer the numbered assessment items in this presentation, use the Slide Show view. (See Slide 10 for an example.)
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  • Table of Contents Inverse Operations One Step Equations Two Step Equations Multi-Step Equations Distributing Fractions in Equations Graphing & Writing Inequalities with One Variable Click on a topic to go to that section. The Distributive Property and Factoring Combining Like Terms Simple Inequalities involving Addition & Subtraction Simple Inequalities involving Multiplication & Division Common Core Standards: 7.EE.1, 7.EE.3, 7.EE.4 Simplifying Algebraic Expressions Translating Between Words and Equations Commutative and Associative Properties Using Numerical and Algebraic Expressions and Equations
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  • Commutative and Associative Properties Return to table of contents
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  • Commutative Property of Addition: The order in which the terms of a sum are added does not change the sum. a + b = b + a 5 + 7 = 7 + 5 12= 12 Commutative Property of Multiplication: The order in which the terms of a product are multiplied does not change the product. ab = ba 4(5) = 5(4)
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  • Associative Property of Addition: The order in which the terms of a sum are grouped does not change the sum. (a + b) + c = a + (b + c) (2 + 3) + 4 = 2 + (3 + 4) 5 + 4 = 2 + 7 9 = 9
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  • The Commutative Property is particularly useful when you are combining integers. Example: -15 + 9 + (-4)= -15 + (-4) + 9=Changing it this way allows for the -19 + 9 = negatives to be added together first. -10
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  • Associative Property of Multiplication: The order in which the terms of a product are grouped does not change the product.
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  • 1Identify the property of -5 + 3 = 3 + (-5) ACommutative Property of Addition BCommutative Property of Multiplication CAssociative Property of Addition DAssociative Property of Multiplication
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  • 2Identify the property of a + (b + c) = (a + c) + b ACommutative Property of Addition BCommutative Property of Multiplication CAssociative Property of Addition DAssociative Property of Multiplication
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  • 3 Identify the property of (3 * (-4)) * 8 = 3 * ((-4) * 8) ACommutative Property of Addition BCommutative Property of Multiplication CAssociative Property of Addition DAsociative Property of Multiplication
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  • Discuss why using the Commutative Property would be useful with the following problems: 1. 4 + 3 + (-4) 2. -9 x 3 x 0 3. -5 x 7 x -2 4. -8 + 1 + (-6)
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  • Combining Like Terms Return to table of contents
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  • An Algebraic Expression - contains numbers, variables and at least one operation.
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  • Like terms: terms in an expression that have the same variable raised to the same power Examples: LIKE TERMS NOT LIKE TERMS 6x and 2x 6x 2 and 2x 5y and 8y 5x and 8y 4x 2 and 7x 2 4x 2 y and 7xy 2
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  • 4 Identify all of the terms like 2x A5x B3x 2 C5y D12y E2
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  • 5 Identify all of the terms like 8y A9y B4y 2 C7y D8 E-18x
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  • 6 Identify all of the terms like 8xy A8x B3x 2 y C39xy D4y E-8xy
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  • 7 Identify all of the terms like 2y A51w B2x C3y D2w E-10y
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  • 8 Identify all of the terms like 14x 2 A-5x B8x 2 C13y 2 Dx E-x 2
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  • If two or more like terms are being added or subtracted, they can be combined. To combine like terms add/subtract the coefficient but leave the variable alone. 7x +8x =15x 9v-2v = 7v
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  • Sometimes there are constant terms that can be combined. 9 + 2f + 6 = 2f + 15 Sometimes there will be both coeffients and constants to be combined. 3g + 7 + 8g - 2 11g + 5 Notice that the sign before a given term goes with the number.
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  • Try These: 1.) 2b +6g(3) + 4f + 9f 2.) 9j + 3 + 24h + 6 + 7h + 3 3.) 7a + 4 + 2a -19 + 8c -12 + 5c 4.) 8x + 56xy + 5y
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  • 98x + 3x = 11x A True B False
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  • 107x + 7y = 14xy A True B False
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  • 11 2x + 3x = 5x A True B False
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  • 12 9x + 5y = 14xy A True B False
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  • 13 6x + 2x = 8x 2 A True B False
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  • 14 -15y + 7y = -8y A True B False
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  • 15 -6 + y + 8 = 2y A True B False
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  • 16 -7y + 9y = 2y A True B False
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  • 179x + 4 + 2x = A15x B11x + 4 C13x + 2x D9x + 6x
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  • 1812x + 3x + 7 - 5 A15x + 7 - 5 B13x C17x D15x + 2
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  • 19-4x - 6 + 2x - 14 A-22x B-2x - 20 C-6x +20 D22x
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  • The Distributive Property and Factoring Return to table of contents
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  • An Area Model Imagine that you have two rooms next to each other. Both are 4 feet long. One is 7 feet wide and the other is 3 feet wide. 4 7 3 How could you express the area of those two rooms together?
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  • 4 7 +3 Either way, the area is 40 feet 2 : You could add 7 + 3 and then multiply by 4 4(7+3)= 4(10)= 40 OR You could multiply 4 by 7, then 4 by 3 and add them 4(7) + 4(3) = 28 + 12 = 40 4 3 7 4
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  • An Area Model Imagine that you have two rooms next to each other. Both are 4 yards long. One is 3 yards wide and you don't know how wide the other is. 4 x 3 How could you express the area of those two rooms together?
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  • 4 x + 3 You cannot add x and 3 because they aren't like terms, so you can only do it by multiplying 4 by x and 4 by 3 and adding 4(x) + 4(3)= 4x + 12 The area of the two rooms is 4x + 12 (Note: 4x cannot be combined with 12)
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  • The Distributive Property Finding the area of the rectangles demonstrates the distributive property. Use the distributive property when expressions are written like so: a(b + c) 4(x + 2) 4(x) + 4(2) 4x + 8 The 4 is distributed to each term of the sum (x + 2)
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  • Write an expression equivalent to: 5(y + 4) 5(y) + 5(4) 5y + 20 6(x + 2)3(x + 4) 4(x - 5) 7(x - 1) Remember to distribute the 5 to the y and the 4
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  • The Distributive Property is often used to eliminate the parentheses in expressions like 4(x + 2). This makes it possible to combine like terms in more complicated expressions. EXAMPLE: -2(x + 3) = -2(x) + -2(3) = -2x + -6 or -2x - 6 3(4x - 6) = 3(4x) - 3(6) = 12x - 18 -2 (x - 3) = -2(x) - (-2)(3) = -2x + 6 TRY THESE: 3(4x + 2) = -1(6m + 4) = -3(2x - 5) = Be careful with your signs!
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  • Keep in mind that when there is a negative sign on the outside of the parenthesis it really is a -1. For example: -(2x + 7) = -1(2x + 7) = -1(2x) + -1(7) = -2x - 7 What do you notice about the original problem and its answer? The numbers are turned to their opposites. Remove to see answer. Try these: -(9x + 3) = -(-5x + 1) = -(2x - 4) = -(-x - 6) =
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  • 20 4(2 + 5) = 4(2) + 5 A True B False
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  • 21 8(x + 9) = 8(x) + 8(9) A True B False
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  • 22 -4(x + 6) = -4 + 4(6) A True B False
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  • 23 3(x - 4) = 3(x) - 3(4) A True B False
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  • 24Use the distributive property to rewrite the expression without parentheses 3(x + 4) A3x + 4 B3x + 12 Cx + 12 D7x
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  • 25Use the distributive property to rewrite the expression without parentheses 5(x + 7) Ax + 35 B5x + 7 C5x + 35 D40x
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  • 26Use the distributive property to rewrite the expression without parentheses (x + 5)2 A2x + 5 B2x + 10 Cx + 10 D12x
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  • 27Use the distributive property to rewrite the expression without parentheses 3(x - 4) A3x - 4 Bx - 12 C3x - 12 D9x
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  • 28Use the distributive property to rewrite the expression without parentheses 2(w - 6) A2w - 6 Bw - 12 C2w - 12 D10w
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  • 29Use the distributive property to rewrite the expression without parentheses -4(x - 9) A-4x - 36 Bx - 36 C4x - 36 D-4x + 36
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  • 30Use the distributive property to rewrite the expression without parentheses 5.2(x - 9.3) A-5.2x - 48.36 B5.2x - 48.36 C-5.2x + 48.36 D-48.36x
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  • 31Use the distributive property to rewrite the expression without parentheses A B C D
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  • We can also use the Distributive Property in reverse. This is called Factoring. When we factor an expression, we find all numbers or variables that divide into all of the parts of an expression. Example: 7x + 35Both the 7x and 35 are divisible by 7 7(x + 5)By removing the 7 we have factored the problem We can check our work by using the distributive property to see that the two expressions are equal.
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  • We can factor with numbers, variables, or both. 2x + 4y = 2(x + 2y) 9b + 3 = 3(3b + 1) -5j - 10k + 25m = -5(j + 2k - 5m) *Careful of your signs 4a + 6a + 8ab = 2a(2 + 3 + 4b)
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  • Try these: Factor the following expressions: 1.) 6b + 9c = 2.) -2h - 10j = 3.) 4a + 20ab + 12abc =
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  • 32Factor the following: 4p + 24q A4 (p + 24q) B2 (2p + 12q) C4(p + 6q) D2 (2p + 24q)
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  • 33Factor the following: 5g + 15h A3(g + 5h) B5(g + 3h) C5(g + 15h) D5g (1 + 3h)
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  • 34Factor the following: 3r + 9rt + 15rx A3(r+ 3rt + 5rx) B3r(1 + 3t + 5x) C3r (3t + 5x) D3 (r + 9rt + 15rx)
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  • 35Factor the following: 2v+7v+14v A7(2v + v + 2v) B7v(2 + 1 + 2) C7v (1 + 2) Dv(2 + 7 + 14)
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  • 36Factor the following: -6a - 15ab - 18abc A-3a(2 + 5b + 6bc) B3a(2+ 5b + 6bc) C-3(2a - 5b - 6bc) D-3a (2 -5b - 6bc)
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  • -What divides into the expression: -5n - 20mn - 10np
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  • -If a regular pentagon has a perimeter of 10x + 25, what does each side equal?
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  • Simplifying Algebraic Expressions Return to table of contents
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  • Now we will use what we know about combining like terms and the distributive property to simplify algebraic expressions. Remember, like terms have the same variable and same exponent.
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  • To simplify: 4 + 5(x + 3) First Distribute 4 + 5(x) + 5(3) 4 + 5x + 15 Then combine Like Terms 5x + 19 Notice that when combining like terms, you add/subtract the coefficients but the variable remains the same. Remember that you can combine coefficient or constant terms.
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  • 37 7x +3(x - 4) = 10x - 4 A True B False
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  • 38 8 +(x + 3)5 = 5x + 11 A True B False
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  • 39 4 +(x - 3)6 = 6x -14 A True B False
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  • 40 2x + 3y + 5x + 12 = 10xy + 12 A True B False
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  • 41 5x 2 + 2x + 7(x + 1) + x 2 = 6x 2 + 9x + 7 A True B False
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  • 42 2x 3 + 4x 2 + 6(x 2 + 3x) + x = 2x 3 + 10x 2 + 4x A True B False
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  • 43The lengths of the sides of home plate in a baseball field are represented by the expressions in the accompanying figure. A5xyz Bx 2 + y 3 z C2x + 3yz D2x + 2y + yz yz y y x x From the New York State Education Department. Office of Assessment Policy, Development and Administration. Internet. Available from www.nysedregents.org/IntegratedAlgebra; accessed 17, June, 2011. Which expression represents the perimeter of the figure?
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  • 44A rectangle has a width of x and a length that is double that. What is the perimeter of the rectangle? A 4x B6x C8x D10x
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  • Inverse Operations Return to table of contents
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  • What is an equation? An equation is a mathematical statement containing an equal sign to show that two expressions are equal. 2 + 3 = 5 9 2 = 7 5 + 3 = 1 + 7 An algebraic equation is just an equation that has algebraic symbols in one or both of the expressions. 4x = 24 9 + h = 15
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  • Equations can also be used to state the equality of two expressions containing one or more variables. In real numbers we can say, for example, that for any given value of x it is true that 4x + 1 = 13 x = 3 because 4(3) + 1 = 13 12 + 1 = 13 13 = 13
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  • An equation can be compared to a balanced scale. Both sides need to contain the same quantity in order for it to be "balanced".
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  • For example, 9+ 11 = 6 + 14 represents an equation because both sides simplify to 20. 9 + 11 = 6 + 14 20 = 20 Any of the numerical values in the equation can be represented by a variable. Examples: 15 + c = 25 x + 10 = 25 15 + 10 = y
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  • When solving equations, the goal is to isolate the variable on one side of the equation in order to determine its value (the value that makes the equation true).
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  • In order to solve an equation containing a variable, you need to use inverse (opposite/undoing) operations on both sides of the equation. Let's review the inverses of each operation: Addition Subtraction Multiplication Division Square Square Root
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  • There are two questions to ask when solving an equation: *What operation is in the equation? *What is the inverse of that operation (This will be the operation you use to solve the equation.)?
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  • A good phrase to remember when doing equations is: Whatever you do to one side of the equation, you do to the other. For example, if you add three on one side of the equal sign you must add three to the other side as well to keep the equation in balance.
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  • To solve for "x" in the following equation... x + 7 = 32 Determine what operation is being shown (in this case, it is addition). Do the inverse to both sides (in this case, it is subtraction). x + 7 = 32 - 7 -7 x = 25 In the original equation, replace x with 25 and see if it makes the equation true. x + 7 = 32 25 + 7 = 32 32 = 32
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  • For each equation, write the inverse operation needed to solve for the variable. a.) y +7 = 14 subtract 7 b.) a - 21 = 10 add 21 c.) 5s = 25 divide by 5 d.) x = 5 multiply by 12 12 move
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  • Think about this... To solve c - 3 = 12 Which method is better? Why? Kendra Added 3 to each side of the equation c - 3 = 12 +3 +3 c = 15 Ted Subtracted 12 from each side, then added 15. c - 3 = 12 -12 -12 c - 15 = 0 +15 +15 c = 15
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  • 45What is the inverse operation needed to solve this equation? 2x = 14 AAddition BSubtraction CMultiplication DDivision
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  • 46What is the inverse operation needed to solve this equation? x - 3 = -12 AAddition BSubtraction CMultiplication DDivision
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  • 47What is the inverse operation needed to solve this problem? -2 + x = 9 AAddition BSubtraction CMultiplication DDivision
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  • One Step Equations Return to table of contents
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  • To solve equations, you must work backwards through the order of operations to find the value of the variable. Remember to use inverse operations in order to isolate the variable on one side of the equation. Whatever you do to one side of an equation, you MUST do to the other side!
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  • Examples: y + 3 = 13 - 3 -3 The inverse of adding 3 is subtracting 3 y = 10 4m = 32 4 4 The inverse of multiplying by 4 is dividing by 4 m = 8 Remember - whatever you do to one side of an equation, you MUST do to the other!!!
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  • x - 5 = 2 +5 +5 x = 7 x + 5 = -14 -5 -5 x = -19 2 = x - 4 +4 6 = x 6 = x + 1 5 = x 12 = x + 17 -17 -5 = x x + 9 = 5 -9 -9 x = -4 One Step Equations Solve each equation then click the box to see work & solution. click to show inverse operation click to show inverse operation click to show inverse operation click to show inverse operation click to show inverse operation click to show inverse operation
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  • One Step Equations 4x = 16 4 4 x = 4 -2x = -12 -2 -2 x = 6 -20 = 5x 5 5 -4 = x x 2 x = 18 = 9 (2) x -6 x = -216 = 36 (-6) click to show inverse operation click to show inverse operation click to show inverse operation click to show inverse operation click to show inverse operation
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  • 48 Solve. x - 7 = 19
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  • 49 Solve. j + 15 = 17
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  • 50 Solve. 42 = 6y
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  • 51 Solve. -115 = -5x
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  • 52 Solve. = 12 x 9
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  • 53 Solve. w - 17 = 37
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  • 54 Solve. -3 = x 7
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  • 55 Solve. 23 + t = 11
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  • 56 Solve. 108 = 12r
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  • Sometimes the operation can be confusing. For example: -2 + x = 7 This looks like you should use subtraction to undo the problem. However, -2 + x = 7 is the same as x - 2 = 7 so while it appears to be addition, it is really subtraction. In order to undo this we can add. -2 + x = 7 x - 2 = 7 +2 +2 x = 9OR-2 + x = 7 - (-2) -(-2)+2 +2 x = 9
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  • -2 + x = 7 -2 = -2 -4 + x = 5 This did not cancel out anything. -2 + x = 7 +2+2 x = 9 This did cancel out to find the answer. -2 + x = 7 x - 2 = 7 +2 +2 x = 9 This is the same as the middle problem
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  • Try these: 1.) -4 + b = 7 2.) -2 + r = 4 3.) -3 + w = 6 4.) -5 + c = 9
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  • Think about this... In the expression To which does the "-" belong? Does it belong to the x? The 3? Both? The answer is that there is one negative so it is used once with either the variable or the 3. Generally, we assign it to the 3 to avoid creating a negative variable. So:
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  • 57 Solve.
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  • 58 Solve. -5 + q = 15
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  • 59 Solve.
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  • 60 Solve
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  • 61 Solve.
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  • 62 Solve.
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  • 63 Solve.
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  • Sometimes you will have an equation where you are multiplying a variable by a fraction.
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  • To undo the fraction you: Multiply by the Reciprocal of the Coefficent This means that you will flip the fraction and then multiply **Dividing by a fraction is the same as multiplying by its reciprocal
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  • 1 times any number is itself so this is why it can cancel out.
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  • 64 Solve.
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  • 65 Solve
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  • 66 Solve.
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  • Two-Step Equations Return to table of contents
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  • Sometimes it takes more than one step to solve an equation. Remember that to solve equations, you must work backwards through the order of operations to find the value of the variable. This means that you undo in the opposite order (PEMDAS): 1st: Addition & Subtraction 2nd: Multiplication & Division 3rd: Exponents 4th: Parentheses Whatever you do to one side of an equation, you MUST do to the other side!
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  • Examples: 4x + 2 = 10 - 2 - 2 Undo addition first 4x = 8 4 4 Undo multiplication second x = 2 -2y - 9 = -13 + 9 + 9 Undo subtraction first -2y = -4 -2 -2 Undo multiplication second y = 2 Remember - whatever you do to one side of an equation, you MUST do to the other!!!
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  • 5b + 3 = 18 -3 -3 5b = 15 5 5 b = 3 3j - 4 = 14 +4 +4 3j = 18 3 3 j = 6 -2x + 3 = -1 - 3 -3 -2x = -4 -2 -2 x = 2 Two Step Equations Solve each equation then click the box to see work & solution. -2m - 4 = 22 +4 +4 -2m = 26 -2 -2 m = -13 +5 = +5 t = 15 w + 6 = 10 2 -6 -6 w 2 = 4 2 2 w = 8
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  • 67 Solve the equation. 5x - 6 = -56
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  • 68 Solve the equation. 14 = 3c + 2
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  • 69 Solve the equation. x 5 - 4 = 24
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  • 70 Solve the equation. 5r - 2 = -12
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  • 71Solve the equation. 14 = -2n - 6
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  • 72 Solve the equation. + 7 = 13 x 5
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  • 73 Solve the equation. + 2 = -10 x 3 -
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  • 74 Solve the equation.
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  • 75 Solve the equation.
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  • 76Solve the equation.
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  • 77Solve the equation.
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  • 78 Solve -3 5 1 2 x + = 1 10
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  • 79 Solve the equation.
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  • 80Solve the equation.
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  • Multi-Step Equations Return to table of contents
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  • Steps for Solving Multiple Step Equations As equations become more complex, you should: 1. Simplify each side of the equation. (Combining like terms and the distributive property) 2. Use inverse operations to solve the equation. Remember, whatever you do to one side of an equation, you MUST do to the other side!
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  • Examples: 5x + 7x + 4 = 28 12x + 4 = 28 Combine Like Terms -4 - 4 Undo Addition 12x = 24 12 12 Undo Multiplication x = 2 -1 = 2r - 7r +19 -1 = -5r + 19 Combine Like Terms -19 = - 19 Undo Subtraction -20 = -5r -5 -5Undo Multiplication 4 = r
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  • Try these. 12h - 10h + 7 = 25 -17q + 7q -13 = 27 17 - 9f + 6 = 140 h = 9 q = - 4 f = -13
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  • Always check to see that both sides of the equation are simplified before you begin solving the equation. Sometimes, you need to use the distributive property in order to simplify part of the equation. Remember: The distributive property is a(b + c) = ab + ac Examples 5(20 + 6) = 5(20) + 5(6) 9(30 - 2) = 9(30) - 9(2) 3(5 + 2x) = 3(5) + 3(2x) -2(4x - 7) = -2(4x) - (-2)(7)
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  • Examples: 2(b - 8) = 28 2b - 16 = 28 Distribute the 2 through (b - 8) +16 +16 Undo subtraction 2b = 44 2 2 Undo multiplication b = 22 3r + 4(r - 2) = 13 3r + 4r - 8 = 13Distribute the 4 through (r - 2) 7r - 8 = 13 Combine Like Terms +8 +8 Undo subtraction 7r = 21 7 7 Undo multiplication r = 3
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  • Try these. 3(w - 2) = 9 4(2d + 5) = 92 6m + 2(2m + 7) = 54 w = 5 d = 9 m = 4
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  • 81 Solve. 9 + 3x + x = 25
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  • 82 Solve -8e + 7 +3e = -13
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  • 83 Solve. -27 = 8x - 4 - 2x - 11
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  • 84 Solve. n - 2 + 4n - 5 = 13
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  • 85 Solve. 32 = f - 3f + 6f
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  • 86 Solve. 6g - 15g + 8 - 19 = -38
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  • 87 Solve. 3(a - 5) = -21
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  • 88 Solve. 4(x + 3) = 20
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  • 89Solve. 3 = 7(k - 2) + 17
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  • 90 Solve. 2(p + 7) -7 = 5
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  • 91 Solve. 3m -1m + 3(m-2) = 19.75
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  • 92 Solve.
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  • 93 Solve.
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  • 94 Solve.
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  • Distributing Fractions in Equations Return to table of contents
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  • Remember... 1. Simplify each side of the equation. 2. Solve the equation. (Undo addition and subtraction first, multiplication and division second) Remember, whatever you do to one side of an equation, you MUST do to the other side!
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  • There is more than one way to solve an equation with a fraction coefficient. While you can, you don't need to distribute. Multiply by the reciprocal Multiply by the LCD (-3 + 3x) = 3 5 72 5 (-3 + 3x) = 3 5 72 5 (-3 + 3x) = 3535 72 5 3 5 3 -3 + 3x = 24 +3 3x = 27 3 3 x = 9 (-3 + 3x) = 3 5 72 5 (-3 + 3x) = 3 5 72 5 5 5 3(-3 + 3x) = 72 -9 + 9x = 72 +9 +9 9x = 81 9 9 x = 9
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  • Some problems work better when you multiply by the reciprocal and some work better multiplying by the LCM. Which strategy would you use for the following? Why?
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  • 95 Solve.
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  • 96 Solve.
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  • (8 - 3c) = 2 3 16 3 97 Solve.
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  • 98 Solve.
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  • 99 Solve.
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  • Translating Between Words and Expressions Return to table of contents
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  • List words that indicate addition
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  • List words that indicate subtraction
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  • List words that indicate multiplication
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  • List words that indicate division
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  • List words that indicate equals
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  • Be aware of the difference between "less" and "less than". For example: "Eight less three" and "Three less than Eight" are equivalent expressions. So what is the difference in wording? Eight less three: 8 - 3 Three less than eight: 8 - 3 When you see "less than", you need to switch the order of the numbers.
  • Slide 178
  • As a rule of thumb, if you see the words "than" or "from" it means you have to reverse the order of the two items on either side of the word. Examples: 8 less than b means b - 8 3 more than x means x + 3 x less than 2 means 2 - x _______________ click to reveal _______________
  • Slide 179
  • The many ways to represent multiplication... How do you represent "three times a"? (3)(a)3(a) 3 a3a The preferred representation is 3a When a variable is being multiplied by a number, the number (coefficient) is always written in front of the variable. The following are not allowed: 3xa... The multiplication sign looks like another variable a3... The number is always written in front of the variable
  • Slide 180
  • Representation of division... How do you represent "b divided by 12"? b 12 b 12 b 12
  • Slide 181
  • When choosing a variable, there are some that are often avoided: l, i, t, o, O, s, S Why might these be avoided? It is best to avoid using letters that might be confused for numbers or operations. In the case above (1, +, 0, 5)
  • Slide 182
  • Three times j Eight divided by j j less than 7 5 more than j 4 less than j 1 2 3 4 5 6 7 8 9 0 + - TRANSLATE THE WORDS INTO AN ALGEBRAIC EXPRESSION j - - - ++
  • Slide 183
  • 23 + m The sum of twenty-three and m Write the expression for each statement. Then check your answer.
  • Slide 184
  • d - 24 Twenty-four less than d Write the expression for each statement. Then check your answer.
  • Slide 185
  • 4(8-j) Write the expression for each statement. Remember, sometimes you need to use parentheses for a quantity. Four times the difference of eight and j
  • Slide 186
  • 7w 12 The product of seven and w, divided by 12 Write the expression for each statement. Then check your answer.
  • Slide 187
  • (6+p) 2 Write the expression for each statement. Then check your answer. The square of the sum of six and p
  • Slide 188
  • 100The quotient of 200 and the quantity of p times 7 A200 7p B200 - (7p) C200 7p D7p 200
  • Slide 189
  • 101 35 multiplied by the quantity r less 45 A35r - 45 B35(45) - r C35(45 - r) D35(r - 45)
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  • 102Mary had 5 jellybeans for each of 4 friends. A5 + 4 B5 - 4 C5 x 4 D5 4
  • Slide 191
  • 103If n + 4 represents an odd integer, the next larger odd integer is represented by An + 2 Bn + 3 Cn + 5 Dn + 6 From the New York State Education Department. Office of Assessment Policy, Development and Administration. Internet. Available from www.nysedregents.org/IntegratedAlgebra; accessed 17, June, 2011.
  • Slide 192
  • 104 a less than 27 A27 - a B a 27 Ca - 27 D27 + a
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  • 105If h represents a number, which equation is a correct translation of: Sixty more than 9 times a number is 375? A9h = 375 B9h + 60 = 375 C9h - 60 = 375 D60h + 9 = 375 From the New York State Education Department. Office of Assessment Policy, Development and Administration. Internet. Available from www.nysedregents.org/IntegratedAlgebra; accessed 17, June, 2011.
  • Slide 194
  • Using Numerical and Algebraic Expressions and Equations Return to table of contents
  • Slide 195
  • We can use our algebraic translating skills to solve other problems. We can use a variable to show an unknown. A constant will be any fixed amount. If there are two separate unknowns, relate one to the other.
  • Slide 196
  • The school cafeteria sold 225 chicken meals today. They sold twice the number of grilled chicken sandwiches than chicken tenders. How many of each were sold? 2c + c = 225 chicken sandwiches chicken tenders total meals c + 2c = 225 3c = 225 3 3 c = 75 The cafeteria sold 150 grilled chicken sandwiches and 75 tenders.
  • Slide 197
  • Julie is matting a picture in a frame. Her frame is 9 inches wide and her picture is 7 inches wide. How much matting should she put on either side? 2m + 7 = 9 -7 -7 2m = 2 2 2 m = 1 Julie needs 1 inches on each side. 1414 1212 1212 1414 9 both sides of the mat size of picture size of frame 1212 1212
  • Slide 198
  • Many times with equations there will be one number that will be the same no matter what (constant) and one that can be changed based on the problem (variable and coefficient). Example: George is buying video games online. The cost of the video is $30.00 per game and shipping is a flat fee of $7.00. He spent a total of $127.00. How many games did he buy in all?
  • Slide 199
  • George is buying video games online. The cost of the video is $30.00 per game and shipping is a flat fee of $7.00. He spent a total of $127.00. How many games did he buy in all? Notice that the video games are "per game" so that means there could be many different amounts of games and therefore many different prices. This is shown by writing the amount for one game next to a variable to indicate any number of games. 30g cost of one video game number of games
  • Slide 200
  • George is buying video games online. The cost of the video is $30.00 per game and shipping is a flat fee of $7.00. He spent a total of $127.00. How many games did he buy in all? Notice also that there is a specific amount that is charged no matter what, the flat fee. This will not change so it is the constant and it will be added (or subtracted) from the other part of the problem. 30g + 7 cost of one video game number of games the cost of the shipping
  • Slide 201
  • George is buying video games online. The cost of the video is $30.00 per game and shipping is a flat fee of $7.00. He spent a total of $127.00. How many games did he buy in all? "Total" means equal so here is how to write the rest of the equation. 30g + 7 = 127 cost of one video game number of games the total amount the cost of the shipping
  • Slide 202
  • George is buying video games online. The cost of the video is $30.00 per game and shipping is a flat fee of $7.00. He spent a total of $127.00. How many games did he buy in all? Now we can solve it. 30g + 7 = 127 -7 30g = 120 30 30 g = 4George bought 4 video games.
  • Slide 203
  • 106Lorena has a garden and wants to put a gate to her fence directly in the middle of one side. The whole length of the fence is 24 feet. If the gate is 4 feet, how many feet should be on either side of the fence? 1212
  • Slide 204
  • 107Lewis wants to go to the amusement park with his family. The cost is $12.00 for parking plus $27.00 per person to enter the park. Lewis and his family spent $147. Which equation shows this problem? A12p + 27 = 147 B12p + 27p = 147 C27p + 12 = 147 D39p = 147
  • Slide 205
  • 108Lewis wants to go to the amusement park with his family. The cost is $12.00 for parking plus $27.00 per person to enter the park. Lewis and his family spent $147. How many people went to the amusement park WITH Lewis?
  • Slide 206
  • 109Mary is saving up for a new bicycle that is $239. She has $68.00 already saved. If she wants to put away $9.00 per week, how many weeks will it take to save enough for her bicycle? Which equation represents the situation? A9 + 68 = 239 B9d + 68 = 239 C68d + 9 = 239 D77d = 239
  • Slide 207
  • 110Mary is saving up for a new bicycle that is $239. She has $68.00 already saved. If she wants to put away $9.00 per week, how many weeks will it take to save enough for her bicycle?
  • Slide 208
  • 111 You are selling t-shirts for $15 each as a fundraiser. You sold 17 less today then you did yesterday. Altogether you have raised $675. Write and solve an equation to determine the number of t-shirts you sold today. Be prepared to show your equation!
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  • 112Rachel bought $12.53 worth of school supplies. She still needs to buy pens which are $2.49 per pack. She has a total of $20.00 to spend on school supplies. How many packs of pens can she buy? Write and solve an equation to determine the number of packs of pens Rachel can buy. Be prepared to show your equation!
  • Slide 210
  • 113 The length of a rectangle is 9 cm greater than its width and its perimeter is 82 cm. Write and solve an equation to determine the width of the rectangle. Be prepared to show your equation!
  • Slide 211
  • 114 The product of -4 and the sum of 7 more than a number is -96. Write and solve an equation to determine the number. Be prepared to show your equation!
  • Slide 212
  • 115 A magazine company has 2,100 more subscribers this year than last year. Their magazine sells for $182 per year. Their combined income from last year and this year is $2,566,200. Write and solve an equation to determine the number of subscribers they had each year. Be prepared to show your equation! How many subscribers last year?
  • Slide 213
  • 116 A magazine company has 2,100 more subscribers this year than last year. Their magazine sells for $182 per year. Their combined income from last year and this year is $2,566,200. Write and solve an equation to determine the number of subscribers they had each year. Be prepared to show your equation! How many subscribers this year?
  • Slide 214
  • 117 The perimeter of a hexagon is 13.2 cm. Write and solve an equation to determine the length of a side of the hexagon. Be prepared to show your equation!
  • Slide 215
  • Graphing and Writing Inequalities with One Variable Return to table of contents
  • Slide 216
  • When you need to use an inequality to solve a word problem, you may encounter one of the phrases below. Important Words Sample Sentence Equivalent Translation is more thanTrenton is more than 10 miles away. t > 10 is greater thanA is greater than B. A > B must exceedThe speed must exceed 25 mph. The speed is greater than 25 mph. s > 25
  • Slide 217
  • When you need to use an inequality to solve a word problem, you may encounter one of the phrases below. Important Words Sample Sentence EquivalentTranslation cannot exceedTime cannot exceed 60 minutes. Time must be less than or equal to 60 minutes. t < 60 is at mostAt most, 7 students were late for class. Seven or fewer students were late for class. n < 7 is at leastBob is at least 14 years old. Bob's age is greater than or equal to 14. B > 14
  • Slide 218
  • How are these inequalities read? 2 + 2 > 3 Two plus two is greater than 3 2 + 2 4 Two plus two is greater than or equal to 4 2 + 2 < 5 Two plus two is less than 5 2 + 2 5 Two plus two is less than or equal to 5 2 + 2 4 Two plus two is less than or equal to 4 2 + 2 > 3 Two plus two is greater than or equal to 3
  • Slide 219
  • Writing inequalities Let's translate each statement into an inequality. x is less than 10 20 is greater than or equal to y x < 10 words inequality statement translate to 20 > y
  • Slide 220
  • You try a few: 1. 14 is greater than a 2. b is less than or equal to 8 3. 6 is less than the product of f and 20 4. The sum of t and 9 is greater than or equal to 36 5. 7 more than w is less than or equal to 10 6. 19 decreased by p is greater than or equal to 2 7. Fewer than 12 items 8. No more than 50 students 9. At least 275 people attended the play
  • Slide 221
  • Do you speak math? Change the following expressions from English into math. Double a number is at most four. Three plus a number is at least six. 2x 4 3 + x 6 Answer
  • Slide 222
  • Five less than a number is less than twice that number. The sum of two consecutive numbers is at least thirteen. Three times a number plus seven is at least nine. x - 5 < 2x x + (x + 1) 13 3x + 7 > 9 Answer
  • Slide 223
  • 0 1 2 3 4 5 6 7 8 9 10 7.5 $7.50 7.5 at least > An employee earns e A store's employees earn at least $7.50 per hour. Define a variable and write an inequality for the amount the employees may earn per hour. Let e represent an employee's wages.
  • Slide 224
  • Try this: The speed limit on a road is 55 miles per hour. Define a variable and write an inequality.
  • Slide 225
  • 118You have $200 to spend on clothes. You already spent $140 and shirts cost $12. Which equation shows this scenario? A200 < 12x + 140 B200 12x + 140 C200 > 12x + 140 D200 12x + 140
  • Slide 226
  • 119 A sea turtle can live up to 125 years. If one is already 37 years old, which scenario shows how many more years could it live? 125 < 37 + x 125 37 + x A B C125 > 37 + x D 125 37 + x
  • Slide 227
  • 120The width of a rectangle is 3 in longer than the length. The perimeter is no less than 25 inches. A4a + 6 < 25 B4a + 6 25 C4a + 6 > 25 D 4a + 6 25
  • Slide 228
  • 121The absolute value of the sum of two numbers is less than or equal to the sum of the absolute values of the same two numbers. A B C D
  • Slide 229
  • A solution to an inequality is NOT a single number. It will have more than one value. 1023 4 567 89 10 -2-3-4-5-6-7-8-9-10 This would be read as the solution set is all numbers greater than or equal to negative 5. Solution Sets
  • Slide 230
  • Let's name the numbers that are solutions of the given inequality. r > 10 Which of the following are solutions? {5, 10, 15, 20} 5 > 10 is not true So, not a solution 10 > 10 is not true So, not a solution 15 > 10 is true So, 15 is a solution 20 > 10 is true So, 20 is a solution Answer: {15, 20} are solutions of the inequality r > 10
  • Slide 231
  • Let's try another one. 30 4d; {3, 4, 5, 6, 7, 8} 30 4d 30 (4)3 30 12 30 4d 30 (4)4 30 16 30 4d 30 (4)5 30 20 30 4d 30 (4) 6 30 24 30 4d 30 (4)7 30 28 30 4d 30 (4)8 30 32 click to reveal
  • Slide 232
  • Graphing Inequalities - The Circle An open circle on a number shows that the number is not part of the solution. It is used with "greater than" and "less than". The word equal is not included. A closed circle on a number shows that the number is part of the solution. It is used with "greater than or equal to" and "less than or equal to".
  • Slide 233
  • Graphing Inequalities - The Arrow The arrow should always point in the direction of those numbers who satisfy the inequality. *If the variable is on the left side of the inequality, then < and will show an arrow pointing left. *If the variable is on the left side of the inequality, then > and will show an arrow pointing right.
  • Slide 234
  • Notice that < and look like an arrow pointing left and that > and look like an arrow pointing right. But what if the variable isn't on the left? Do the opposite of where the inequality symbol points. 0 -2-3-4 -5 12 34 5
  • Slide 235
  • What is the number in the inequality? What kind of circle should be used? In what direction does the line go? Graphing Inequalities
  • Slide 236
  • Step 1: Rewrite this as x < 5. Step 2: What kind of circle? Because it is less than, it does not include the number 5 and so it is an open circle. 0 -2-3-4 -5 12 34 5 Graphing Inequalities x is less than 5
  • Slide 237
  • Step 4: Draw a line, thicker than the horizontal line, from the dot to the arrow. This represents all of the numbers that fulfill the inequality. Step 3: Draw an arrow on the number line showing all possible solutions. Numbers greater than the variable, go to the right. Numbers less than the variable, go to the left. 0 -2-3-4 -5 12 34 5 x < 5 0 -2-3-4 -5 12 34 5
  • Slide 238
  • Step 1: Rewrite this as x 5. Step 2: What kind of circle? Because it is less than or equal to, it does include the number 5 and so it is a closed circle. 0 -2-3-4 -5 12 34 5 Graphing Inequalities x is less than or equal to 5
  • Slide 239
  • Step 4: Draw a line, thicker than the horizontal line, from the dot to the arrow. This represents all of the numbers that fulfill the inequality. Step 3: Draw an arrow on the number line showing all possible solutions. Numbers greater than the variable, go to the right. Numbers less than the variable, go to the left. 0 -2-3-4 -5 12 34 5 0 -2-3-4 -5 12 34 5 x 5
  • Slide 240
  • 10234567 89 10 -2-3-4-5-6-7-8-9-10 You try Graph the inequality x > 2 Graph the inequality -3 > x 10234567 89 10 -2-3-4-5-6-7-8-9-10 click 2 on the number line for answer click -3 on the number line for answer.05.05.05.05
  • Slide 241
  • Try these. Graph the inequalities. 1. x > -3 0 -2 -3 -4-512 34 5 2. x < 4 0 -2-3-4-512 34 5.05..05.
  • Slide 242
  • Try these. State the inequality shown. 1. 0 -2-3-4-512 34 5 0 -2-3-4-512 34 5 2.
  • Slide 243
  • 122 This solution set would be x > -4. 10234567 89 10 -2-3-4-5-6-7-8-9-10 A True B False
  • Slide 244
  • 0-2-3-4 -5 1234 5 123 Ax > 3 Bx < 3 C Dx > 3 State the inequality shown.
  • Slide 245
  • 5 6 7 8 9 10 11 12 13 14 15 124 A11 < x B11 > x C D11 < x State the inequality shown.
  • Slide 246
  • 0-2-3-4 -5 1234 5 125 Ax > -1 Bx < -1 C Dx > -1 State the inequality shown.
  • Slide 247
  • -5 1 5 0-2-3-4234 126 A-4 < x B-4 > x C-4 < x D-4 > x State the inequality shown.
  • Slide 248
  • 0-2-3-4 -5 1234 5 127 Ax > 0 Bx < 0 C Dx > 0 State the inequality shown.
  • Slide 249
  • Simple Inequalities Involving Addition and Subtraction Return to table of contents
  • Slide 250
  • x + 3 = 13 - 3 - 3 x = 10 Remembers how to solve an algebraic equation? Does 10 + 3 = 13 13 = 13 Be sure to check your answer! Use the inverse of addition
  • Slide 251
  • Solving one-step inequalities is much like solving one-step equations. To solve an inequality, you need to isolate the variable using the properties of inequalities and inverse operations. Remember, whatever you do to one side, you do to the other.
  • Slide 252
  • 12 > x + 5 -5 -5 Subtract to undo addition 7 > x To find the solution, isolate the variable x. Remember, it is isolated when it appears by itself on one side of the equation.
  • Slide 253
  • 7 > x The symbol is > so it is an open circle and it is numbers less than 7 so it goes to the left. 10234567 89 10 -2-3-4-5-6-7-8-9-10
  • Slide 254
  • 10234567 89 10 -2-3-4-5-6-7-8-9-10 A. j + 7 > -2 Solve and graph. -9 is not included in solution set; therefore we graph with an open circle. A. j + 7 > -2 -7 -7 j > -9
  • Slide 255
  • B. r - 2 > 4 Solve and graph. 11101213149876543210 r - 2 > 4 +2 +2 r > 6
  • Slide 256
  • 10234567 89 10 -2-3-4-5-6-7-8-9-10 5 > w - 4 9 > w + 4 w < 5 C. 9 > w + 4 Solve and graph.
  • Slide 257
  • 128 Solve the inequality. 3 < s + 4 ____ < s
  • Slide 258
  • 102 34567 89 10 -2 -3-4-5-6-7-8-9 -10 A 102 34567 89 10 -2 -3-4-5-6-7-8-9 -10 B 102 34567 89 10 -2 -3-4-5-6-7-8-9 -10 C 102 34567 89 10 -2 -3-4-5-6-7-8-9 -10 D 129 Solve the inequality and graph the solution. -4 + b < -2
  • Slide 259
  • 102 34567 89 10 -2 -3-4-5-6-7-8-9 -10 A 102 34567 89 10 -2 -3-4-5-6-7-8-9 -10 B 102 34567 89 10 -2 -3-4-5-6-7-8-9 -10 C 102 34567 89 10 -2 -3-4-5-6-7-8-9 -10 D 130 Solve the inequality and graph the solution. -8 > b - 5
  • Slide 260
  • 131Solve the inequality. m + 6.4 < 9.6 m < ______
  • Slide 261
  • Simple Inequalities Involving Multiplication and Division Return to table of contents
  • Slide 262
  • Since x is multiplied by 3, divide both sides by 3 for the inverse operation. Multiplying or Dividing by a Positive Number 3x > -36 3 3 x > -12
  • Slide 263
  • Solve the inequality. 2 3 r < 4 3 2 () r < 6 Since r is multiplied by 2/3, multiply both sides by the reciprocal of 2/3. 2 3 r < 4 3 2 ( )
  • Slide 264
  • 132 3k > 18 10234567 89 10 -2-3-4-5-6-7-8-9-10 A B C 10234567 89 10 -2-3-4-5-6-7-8-9-10 D 10234567 89 10 -2-3-4-5-6-7-8-9-1010234567 89 10 -2-3-4-5-6-7-8-9-10
  • Slide 265
  • 133 A B C -30 > 3q 10 > q -10 < q -10 > q D 10 < q
  • Slide 266
  • 134 X 2 A B C 102 34567 89 10 -2 -3-4-5-6-7-8-9 -10 D 102 34567 89 10 -2 -3-4-5-6-7-8-9 -10102 34567 89 10 -2 -3-4-5-6-7-8-9 -10102 34567 89 10 -2 -3-4-5-6-7-8-9 -10 < -3
  • Slide 267
  • 135 A B C g > 27 g > 36 g > 108 g > 36 D g > 108 3 4
  • Slide 268
  • 136 A B C -21 > 3d d > -7 d < -7 D
  • Slide 269
  • Sometimes you must multiply or divide to isolate the variable. Multiplying or dividing both sides of an inequality by a negative number gives a surprising result. Now let's see what happens when we multiply or divide by negative numbers.
  • Slide 270
  • 1.Write down two numbers and put the appropriate inequality ( ) between them. 2.Apply each rule to your original two numbers from step 1 and simplify. Write the correct inequality ( ) between the answers. A. Add 4 B. Subtract 4 C. Multiply by 4 D. Multiply by -5 E. Divide by 4 F. Divide by -4
  • Slide 271
  • 3.What happened with the inequality symbol in your results? 4. Compare your results with the rest of the class. 5. What pattern(s) do you notice in the inequalities? How do different operations affect inequalities? Write a rule for inequalities.
  • Slide 272
  • Let's see what happens when we multiply this inequality by -1. 5 > -1 -1 5 ? -1 -1 -5 ? 1 -5 < 1 We know 5 is greater than -1 Multiply both sides by -1 Is -5 less than or greater than 1? You know -5 is less than 1, so you should use < What happened to the inequality symbol to keep the inequality statement true?
  • Slide 273
  • The direction of the inequality changes only if the number you are using to multiply or divide by is negative. Helpful Hint
  • Slide 274
  • 10234567 89 10 -2-3-4-5-6-7-8-9-10 Dividing each side by -3 changes the > to 18 -3y < 18 -3 -3 y < -6 Solve and graph. A.
  • Slide 275
  • Divide each side by -7 Flip the sign because you divided by a negative. 10234567 89 10 -2-3-4-5-6-7-8-9-10 -7m > -28 -7m < -28 -7 -7 m < 4 Solve and graph. B.
  • Slide 276
  • Divide each side by 5. The sign does NOT change because you did not divide by a negative. 5m > -25 5 5 m > -5 Solve and graph. C. 10234567 89 10 -2-3-4-5-6-7-8-9-10
  • Slide 277
  • D. -8y > 32 Solve and graph. 10234567 89 10 -2-3-4-5-6-7-8-9-1010234567 89 10 -2-3-4-5-6-7-8-9-10 E. -9f > -54
  • Slide 278
  • 10234567 89 10 -2-3-4-5-6-7-8-9-10 You multiplied by a negative. -r 2 < 5 -2 ( ) r > -10 Multiply both sides by the reciprocal of -1/2. -r 2 > 5-2 () Why did the inequality change?
  • Slide 279
  • 1. -6h < 42 Try these. Solve and graph each inequality. 2. 4x > -20 10234567 89 10 -2-3-4-5-6-7-8-9-1010234567 89 10 -2-3-4-5-6-7-8-9-10
  • Slide 280
  • 3. 5m < 30 Try these. Solve and graph each inequality. 4. > -3 a -2 10234567 89 10 -2-3-4-5-6-7-8-9-1010234567 89 10 -2-3-4-5-6-7-8-9-10
  • Slide 281
  • 137 10234567 89 10 -2-3-4-5-6-7-8-9-10 Solve and graph. 3y < -6
  • Slide 282
  • 138 10234567 89 10 -2-3-4-5-6-7-8-9-10 Solve and graph. x -4 < -2
  • Slide 283
  • 139 10234567 89 10 -2-3-4-5-6-7-8-9-10 Solve and graph. -5y -25
  • Slide 284
  • 140 10234567 89 10 -2-3-4-5-6-7-8-9-10 Solve and graph. n -2 > 2