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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Objective: Solve equations that
involve more than one operation.
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8/12/2019 Pre Algebra Lesson 7 2
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5-Minute Check
1. Rupesh earned some money mowing lawns one month.
He put half of his money into savings. With the rest, he
spent $15 on a new CD, $6 to see a movie, $3 on food,
and he still had $24 left. How much money did Rupeshearn mowing
lawns that month?
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8/12/2019 Pre Algebra Lesson 7 2
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5-Minute Check
1. Rupesh earned some money mowing lawns one month.
He put half of his money into savings. With the rest, he
spent $15 on a new CD, $6 to see a movie, $3 on food,
and he still had $24 left. How much money did Rupeshearn mowing
lawns that month?
$96
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8/12/2019 Pre Algebra Lesson 7 2
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5-Minute Check
1. In an intramural basketball game, Annie made 6 points
more than Roberto. Roberto made half as many points
as Charlie. Charlie made 3 more points than Darla. If
Darla made 9 points, how many points did Annie make?
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8/12/2019 Pre Algebra Lesson 7 2
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5-Minute Check
1. In an intramural basketball game, Annie made 6 points
more than Roberto. Roberto made half as many points
as Charlie. Charlie made 3 more points than Darla. If
Darla made 9 points, how many points did Annie make?
12 points
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
To solve two-step equations, first undo
operations involving numbers without
variables.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Example
Solve b/28 = 20. Check your solution.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Example
Solve b/28 = 20. Check your solution.
b/28 = 20
b/28 + 8 = 20 + 8 Add 8 to each side.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Example
Solve b/28 = 20. Check your solution.
b/28 = 20
b/28 + 8 = 20 + 8b/2 = 28
Add 8 to each side.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Example
Solve b/28 = 20. Check your solution.
b/28 = 20
b/28 + 8 = 20 + 8b/2 = 28
2* b/2 = 28 * 2
Add 8 to each side.
Multiply each side by 2.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Example
Solve b/28 = 20. Check your solution.
b/28 = 20
b/28 + 8 = 20 + 8b/2 = 28
2* b/2 = 28 * 2
b = 56
Add 8 to each side.
Multiply each side by 2.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Example
Solve b/28 = 20. Check your solution.
b/28 = 20
b/28 + 8 = 20 + 8b/2 = 28
2* b/2 = 28 * 2
b = 56
Check: b/28 = 20
Add 8 to each side.
Multiply each side by 2.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Example
Solve b/28 = 20. Check your solution.
b/28 = 20
b/28 + 8 = 20 + 8b/2 = 28
2* b/2 = 28 * 2
b = 56
Check: b/28 = 20
56/28 ?= 20
Add 8 to each side.
Multiply each side by 2.
Replace b with 56.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Example
Solve b/28 = 20. Check your solution.
b/28 = 20
b/28 + 8 = 20 + 8b/2 = 28
2* b/2 = 28 * 2
b = 56
Check: b/28 = 20
56/28 ?= 20
288 ?= 20
Add 8 to each side.
Multiply each side by 2.
Replace b with 56.
Do the division first.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Example
Solve b/28 = 20. Check your solution.
b/28 = 20
b/28 + 8 = 20 + 8b/2 = 28
2* b/2 = 28 * 2
b = 56
Check: b/28 = 20
56/28 ?= 20
288 ?= 20
20 ?= 20
Add 8 to each side.
Multiply each side by 2.
Replace b with 56.
Do the division first.
The solution is 56.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Example
Solve b/28 = 20. Check your solution.
b/28 = 20
b/28 + 8 = 20 + 8b/2 = 28
2* b/2 = 28 * 2
b = 56
Check: b/28 = 20
56/28 ?= 20
288 ?= 20
20 ?= 20
Add 8 to each side.
Multiply each side by 2.
Replace b with 56.
Do the division first.
The solution is 56.
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Application: Solve the following by first writing an
equation.
Teresas grocery bill totaled $12.5. If she bought an item
for
$7.94 and two packs of soft drinks, how much did each pack
ofsoft drinks cost?
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Application: Solve the following by first writing an
equation.
Teresas grocery bill totaled $12.5. If she bought an item
for
$7.94 and two packs of soft drinks, how much did each pack
ofsoft drinks cost?
Answer: $2.28
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8/12/2019 Pre Algebra Lesson 7 2
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7-2 Solving Two-Step Equations
Assignment: 12 - 32 even, 33 - 44 all.
