8. 1
Need Another Example?
2
3
Step-by-Step Example
1. Evaluate 2(n + 3) if n = –4.
2(n + 3) = 2(–4 + 3) Replace n with –4.
Evaluate inside the parentheses.
Multiply.
= 2(–1)
= –2
10. 1
Need Another Example?
2
3
Step-by-Step Example
2. Evaluate 8w – 2v if w = 5 and v = 3.
8w – 2v = 8(5) – 2(3) Replace w with 5 and v with 3.
Do all of the multiplication first.
Subtract 6 from 40.
= 40 – 6
= 34
12. 1
Need Another Example?
2
3
Step-by-Step Example
3. Evaluate 4y3 + 2 if y = 3.
4y3 + 2 = 4(3)3 + 2 Replace y with 3.
Evaluate the power.
Multiply, then add.
= 4(27) + 2
= 110
14. 1
Need Another Example?
2
3
4
5
Step-by-Step Example
4. Athletic trainers use the formula , where a
is a person’s age, to find their minimum training heart rate.
Find Latrina’s minimum training heart rate if she is 15 years old.
Replace a with 15.
Subtract 15 from 220.
Multiply 3 and 205.
= 123 Divide 615 by 5.
Latrina’s minimum training heart rate is 123 beats per minute.
15. Answer
Need Another Example?
The formula for rewriting a Fahrenheit temperature
as a Celsius temperature is , where F
equals the temperature in degrees Fahrenheit.
Find the Celsius equivalent of 77° Fahrenheit.
25°C
16. 1
Need Another Example?
2
3
4
Step-by-Step Example
5. Marisa wants to buy a DVD player that costs $150.
She already saved $25 and plans to save an
additional $10 each week. Write an expression
that represents the total amount of money Marisa
has saved after any number of weeks.
savings of $25 plus ten dollars each week
25 + 10w represents the total saved after any number of weeks.
Words
Variable Let w represent the number of weeks.
Expression 25 + 10 • w
17. Answer
Need Another Example?
Leah has already read 20 pages of a book. She
plans to read 5 pages each day from now on.
Write an expression that represents the total
number of pages she will have read in d days.
20 + 5d
18. 1
Need Another Example?
2
3
4
Step-by-Step Example
6. Refer to Example 5. Will Marisa have saved enough
money to buy the $150 DVD player in 11 weeks?
Use the expression 25 + 10w.
25 + 10w = 25 + 10(11) Replace w with 11.
Multiply.
Add.
= 25 + 110
= 135
Marisa will have saved $135 after 11 weeks. Since $135 < $150,
Marisa will not have enough money to buy the DVD player.
19. Answer
Need Another Example?
The expression 20 + 5d represents the total
number of pages Leah will read in d days. Will
Leah have read more than 60 pages in 7 days?
No, she will have only read 55 pages.
20. How did what you learned
today help you answer the
HOW can you use numbers and symbols
to represent mathematical ideas?
Course 2, Lesson 5-1
Expressions and Equations
21. How did what you learned
today help you answer the
HOW can you use numbers and symbols
to represent mathematical ideas?
Course 2, Lesson 5-1
Expressions and Equations
Sample answers:
• To represent unknown values with variables
• To represent real-world situations with algebraic
expressions
22. Describe a real-world
problem with a variable
or variables. Be sure to
define your variable(s).
Course 2, Lesson 5-1
Ratios and Proportional RelationshipsExpressions and Equations