1. A long distance call costs 10 cents, plus 4.5 cents for each minute. How
much will an 8-minute call cost?
Tina’s Method
I can let m represent the number of minutes. To find the
cost of the call, I can use the algebraic expression
10 4 .5 m. I will evaluate the expression for m 8.
10 4.5m 10 4.5(8) d Replace m with 8.
10 36 d Multiply 4.5 and 8.
46 d Add 10 to 36.
The telephone call will cost 46 cents.
Daryl’s Method
If one minute costs 4.5 cents, then a two-minute call will cost 9 cents.
Four minutes will cost 18 cents, and eight minutes will cost 36 cents.
I need to add the 10 cents. So the total cost is 36 cents 10 cents,
or 46 cents.
Choose a Method
Another long-distance plan charges 5 cents per call, plus 6 cents for each
minute. Find how much a 10-minute call costs with this plan. Describe
your method and explain why you chose it.
Standards Practice AF 1.1
A Practice by Example Write an expression for each verbal description.
Example 1 1. d more than 50 Guided Practice
(page 15) This exercise has been
started for you!
50 d
50 d
2. 23 times q 3. 5 less than m
4. 7 decreased by b 5. p multiplied by 14
For: Examples 1–2 6. f divided by 3 7. the sum of a and 6
Visit: PHSchool.com
Web Code: axe-0103 8. n less than 19 9. 21 divided by w
16 Check Your Understanding Homework prep is in your .

2. Example 2 Write an expression for each verbal description.
(page 15)
10. the number of days in w weeks Guided Practice
This exercise has been
7 started for you!
11. the number of eggs n divided by 9
12. $5 more than the price p
13. 8 lb less than the weight w
14. the number of students s plus 2 teachers
15. $10 multiplied by h hours
16. 175 pages divided by d days
17. Three brothers earn money by doing yard work. The brothers split
the money equally. Write an expression that describes how much
money each brother earns.
B Apply Your Skills 18. Guided Problem Solving A hot-air balloon is at a height of
2,250 ft. It descends 150 ft per min. Find its height after 6, 8,
and 10 min.
• Make a table to show the pattern of the balloon’s height.
• Write an expression for the balloon’s height at m minutes.
Match each expression with its model.
A. B. C.
3 x x x x x
3 ?
19. 3x 20. x 3 21. 3 x
22. Writing in Math Describe a situation you could model with the
expression y 3.
S C A F F O L D E D
Problem Solving Customers in a paint store use the table at the
right to decide how much paint they need.
23. How much paint do you need to paint an Area
area of 800 ft2? (ft.²) Gallons
400 1
24. How many square feet can you paint with 800 2
each gallon of paint? 2,000 5
3,200 8
25. Write an expression for the number of
gallons of paint needed for an area of A ft2.
26. How much paint do you need to paint an area of 2,400 ft2?
27. Paint costs $17.95 per gallon. Write an expression to find the cost of
the paint needed for an area of A ft2.
Chapter 1 Variables and Algebraic Expressions 1-3 Writing Expressions 17