1. Warm Up Solve. 1. x – 17 = 32 2. y + 11 = 41 3. = 18 4. 12x = 108
3. = 18
4. 12x = 108
5. x – 9 = 20 w 5

2. Students in a physical education class were running
40-yard dashes as part of a fitness test. The slowest time in the class was 3.84 seconds slower than the fastest time of 7.2 seconds.
You can write an equation to represent this situation.
The slowest time s minus 3.84 is equal to the fastest
time of 7.2 seconds.
s – 3.84 = 7.2

3. Remember!
You can solve an equation by performing the same operation on both sides of the equation
to isolate the variable.

4. Additional Example 1: Solving Equations by Adding or Subtracting
Solve.
A. n – 2.75 = 8.3
B. a = 42

5. Check It Out: Example 1
Solve.
A. a – 1.35 = –22
B. b = 36

6. Additional Example 2A: Solving Equations by Multiplying or Dividing
Solve. x
= 5.4
4.8

7. Additional Example 2B: Solving Equations by Multiplying and Dividing
Solve.
9 = 3.6d

8. Check It Out: Example 2A
Solve. Justify your steps. c
9.6 = 8

9. Check It Out: Example 2B
Solve. Justify your steps.
9 =
2.5 d

10. Understand the Problem
Additional Example 3: Problem Solving Application
The fee to place a standard classified add is $29.95 for 25 words. The cost for each additional word is $0.25. Isabel has $33.20 to place a classified ad. How many additional words can she purchase? 1
Understand the Problem
List the important information:
• The fee to place a classified add is $29.95 for 25 words.
• The cost for each additional word is $0.25.
• Isabel has $33.20 to place an ad.

11. Additional Example 3 Continued2
Make a Plan
Because you know how much money Isabel has to spend, you can write an equation with w being the number of additional words she can purchase.
w = 33.20

12. Additional Example 3 Continued
Solve 3
w = 33.20

13. Additional Example 3 Continued4
Look Back
You can round to 33, and to 30 to estimate how many additional words Isabel can include.

14. Check It Out: Example 3
Hannah is driving 525 miles to visit her family. She drove miles before she stop to get gas. If she averages 53 miles per hour for the rest of her trip, how many more hours will it take to arrive at her destination?
h = 525