Warm Up

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Warm Up Solve. 1. x 3 11 2. 18 x
4 3. 42 4. 2x 52 5. x 82 172
x 14
x 14
x
x 294
7
x 26
x 254
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Learn to solve equations involving decimals.
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You can solve equations with decimals using
inverse operations just as you solved equations
with whole numbers.
45.20 m 69.95
45.20
45.20
m 24.75
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Additional Example 1A Solving One-Step Equations
with Decimals Solve the equation. Check your
answer.
k 6.2 9.5
6.2 is subtracted from k.
k 6.2 9.5
Add 6.2 to both sides to undo the subtraction.
6.2
6.2
k 15.7
Check
k 6.2 9.5
Substitute 15.7 for k in the equation.
15.7 is the solution.
?
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Additional Example 1B Solving One-Step Equations
with Decimals Solve the equation. Check your
answer.
6k 7.2
k is multiplied by 6.
6k 7.2
Divide both sides by 6 to undo the multiplication.
6k 7.2
k 1.2
Check
6k 7.2
Substitute 1.2 for k in the equation.
1.2 is the solution.
?
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Additional Example 1C Solving One-Step Equations
with Decimals Solve the equation. Check your
answer.
m
0.6
m is divided by 7.
7
Multiply both sides by 7 to undo the division.
7
0.6
7
m 4.2
Check
Substitute 4.2 for m in the equation.
4.2 is the solution.
?
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Additional Example 2A Measurement Application
The area of Emilys floor is 33.75 m2. If its
length is 4.5 meters, what is its width?
area length width
33.75 4.5 w
Write the equation for the problem. Let w be the
width of the room.
33.75 4.5w
33.75 4.5w
Divide both sides by 4.5 to undo the
multiplication.
4.5
4.5
7.5 w
The width of Emilys floor is 7.5 meters.
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Additional Example 2B Measurement Application
If carpet costs 23 per square meter, what is the
total cost to carpet the floor?
total cost area cost of carpet per square
meter
Let C be the total cost. Write the equation for
the problem.
C 33.75 23
Multiply.
C 776.25
The cost of carpeting the floor is 776.25.
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Insert Lesson Title Here
Lesson Quiz
Solve each equation. Check your answer. 1. x
3.9 14.2 2. 8.3 3. x 4.9 16.2 4. 7x
47.6 5. The area of the floor in Devons room is
35.7 m2. If the width is 4.2 m, what is the
length of the bedroom?
x 18.1
x 33.2
x 21.1
x 6.8
8.5 m
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Learn to solve equations by multiplying and
dividing fractions.
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Additional Example 1A Solving Equations by
Multiplying and Dividing Solve each equation.
Write the answer in simplest form.
3
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j 25
5
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Additional Example 1B Solving Equations by
Multiplying and Dividing Solve each equation.
Write the answer in simplest form.
7x
Multiply both sides by the reciprocal of 7.

x
The answer is in simplest form.
x
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Additional Example 1C Solving Equations by
Multiplying and Dividing Solve each equation.
Write the answer in simplest form.
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Divide both sides by .


y , or 9
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Check It Out Example 1A Solve each equation.
Write the answer in simplest form.
3
__
j 19
4
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Check It Out Example 1B Solve each equation.
Write the answer in simplest form.
3x
Multiply both sides by the reciprocal of 3.

x
x
The answer is in simplest form.
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Lesson Quiz
Solve each equation. Write the answer in simplest
form. 1. 3x 2. x 4 3. x
14 4. 9 5. Rebecca used 3 pt of
paint to paint of the trim in her bedroom.
How many pints will Rebecca use for the trim in
the entire bedroom?
x 16
x
y 63
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