1. Additional Examples 1A: Solving Equations with Decimals
Solve.
m = 9
m = 9
Since 4.6 is added to m, subtract 4.6 from both sides to undo the addition.
– 4.6
4.4 m =
Once you have solved an equation, it is a good idea to check your answer. To check your answer, substitute your answer for the variable in the original equation.
Remember!

2. Additional Examples 1B: Solving Equations with Decimals
Solve.
8.2p = –32.8
Since p is multiplied by 8.2, divide both sides by 8.2. –
8.2p 8.2 = –4 p =

3. Additional Examples 1C: Solving Equations with Decimals
Solve.
= 15
x 1.2
x 1.2
= 1.2 • 15
1.2 •
Since x is divided by 1.2, multiply both sides by 1.2.
x = 18

4. Check It Out! Example 1
Solve. A.
m = 3
Since 9.1 is added to m, subtract 9.1 from both sides to undo the addition.
m = 3
–9.1 =
–6.1 m = B.
5.5b = 75.9
Since b is multiplied by 5.5, divide both sides by 5.5. = b
13.8 b =

5. C. Solve. Check It Out! Example 1C y 4.5 = 90
= 4.5 • 90
4.5 •
Since y is divided by 4.5, multiply both sides by 4.5.
y = 405

6. Additional Example 2A: Solving Equations with Fractions
Solve.
= –
3 7
n +
2 7
n + – = – –
3 7
2 7 27
2 7
Since is added to n, subtract
from both sides.
n = –
5 7

7. Additional Example 2B: Solving Equations with Fractions
Solve.
1 6
2 3 y – =
Since is subtracted from y, add
to both sides.
1 6 =
y –
2 3
1 6 +
1 6 +
1 6 = y
4 6
1 6 +
Find a common denominator, 6. = y
5 6

8. Additional Example 2C: Solving Equations with Fractions
Solve.
5 6
5 8 x =
Since x is multiplied by ,
divide both sides by .
5 6
5 6
÷ = ÷
5 8 x 1 1 1 3
5 6 =
5 8 x
6 5 •
Multiply by the reciprocal. Simplify. 1 1 4 1 x =
3 4

9. Solve. Check It Out! Example 2A 1 9 5 9 n + = – n + – = – – 5 9 1 9 19
Since is added to n, subtract
from both sides.
n = –
6 9
n = –
2 3
Simplify.

10. Solve. Check It Out! Example 2B = y – 1 2 3 4
Since is subtracted from y, add
to both sides.
1 2 =
y –
3 4
1 2 +
1 2 +
1 2 = y
3 4
2 4 +
Find a common denominator, 4. = y
5 4 y
= 1
1 4
Simplify.

11. Solve. Check It Out! Example 2C 3 8 3 4 x = Since x is multiplied by ,
divide both sides by .
3 8
3 8
÷ = ÷
3 4 x 1 1 1 2
3 8 =
3 4 x
8 3 •
Multiply by the reciprocal. Simplify. 1 1 1 1
x = 2

12. Additional Example 3: Solving Word Problems Using Equations
1 3
Janice has saved $ This is of what she needs to save to buy a new piece of software. What is the total amount that Janice needs to save?
Write an equation:
Amount Saved
Amount Needed 
1/3 =
1 3 = a 
$21.40

13. Additional Example 3 Continued
Since a is multiplied by ,
divide both sides by .
1 3
= ÷
a x ÷
1 3
1 3
=  a  
3 1
Multiply by the reciprocal. a
= 64.20
Simplify.
Janice needs to save $64.20.

14. Capacity of minivan’s tank
Check It Out! Example 3
Rick’s car holds the amount of gasoline as his
wife’s van. If the car’s gas tank can hold 24
gallons of gasoline, how much gasoline can the tank in the minivan hold?
2 3
Write an equation:
Capacity of minivan’s tank
Capacity of car’s tank •
2/3 =
2 3 g • = 24

15. Check It Out! Example 3 Continued
Since g is multiplied by ,
divide both sides by .
2 3
= 24 ÷
g  ÷
2 3
2 3
= 24  g  
3 2
Multiply by the reciprocal.
g =
722 g
= 36
Simplify.
The minivan can hold 36 gallons of gas.

16. j = –15
5 12
Lesson Quiz
Solve.
x = 41.1
2 3
3 4
1. x – 23.3 = 17.8
2. j + = –14
3 5 d 4 = 2
3 8 1 2
d = 9 1 15
y =
3. 9y = 4.
2 5 5.
Tamara can mow acre in one hour. If her yard is 2 acres, how many hours will it take her to mow the entire yard?
5 hours