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Over Lesson 4–4
A. A
B. B
C. C
D. D
A. 24B. –12C. –18D. –24Solve –3x = –21. Check your solution.A. 9B. 7C. –7D. –8
You have already solved one-step equations. (Lessons 4–3 and 4–4)
• Solve two-step equations.
• Solve real-world problems involving two-step equations.
• two-step equation An equation that contains two operations
Two step equations…scary! Boo!
• Calm down, inverse operations are still the key!
• To further subside your anxiety, they are easy if you remember that algebra is a process you work backwards through. Remember, you know the end, we want the missing piece (like a detective)
Since things are backwards, so are the order of operations (Subtraction, Addition, Division, Multiplication, Exponents, Parenthesis) or…
Sometimes A Dumb Monkey EatsPoop
Even Better, the steps are the same!
• Example: 3n – 6 = 15• 3n – 6 = 15Step 1: Rewrite the problem• 3n – 6 = 15Step 2: Line through =• + 6 + 6 Step 3: Inverse Operation
(SADMEP)• 3n = 21 Repeat Step 2: Line through =• 3 3 Repeat Step 3: Inverse Operation• n = 7 Step 4: Do the math
Step 1: Rewrite the problem Step 2: Draw line through = - 9 - 9 Step 3: Inverse (SADMEP) Repeat Step 2: Draw line Repeat Step 3: Inverse c = 39 Step 4: Do the math
Solve a Two-Step Equation
2m + 8 = 32 Step 1: Write the equation.
Solve 2m + 8 = 32.
m = 12 Step 4: Do the math
2m = 24
– 8 = – 8 Step 2+3:Line through =; inverse
Repeat Steps 2+3
Step 1:Write the equation.
Solve a Two-Step Equation
w = 12 Step 4: Do the math
Repeat Steps 2+3
– 6 =-6 Step 2+3:Line through =; inverse
A. A
B. B
C. C
D. D
A. –70
B. –15
C. 15
D. 70
Solve 5b + 4 = 79.
What if the variable is after subtraction?• Example: 5 – x = 17• 5 – 1x = 17 Step 1: Rewrite the equation• 5 – 1x = 17 Step 2: Draw line through =• - 5 - 5Step 3: Inverse (SADMEP)• - 1x = 12 Repeat Step 2: Draw line through =• -1 -1Repeat Step 3: Inverse (- means -1)• x = -12
A. A
B. B
C. C
D. D
A. 13
B. 5
C. –5
D. –13
Solve 9 = –4 – m.
