6 www c k12 org chapter 1 expressions equations and

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www. c k12 .org Chapter 1. Expressions, Equations, and Functions
Example C
To prevent major accidents or injuries, these horses must be fenced in a rectangular pasture. If the dimensions of the
pasture are 300 feet by 225 feet, how much fencing should the ranch hand purchase to enclose the pasture?
Video Review
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1.2. Expressions with One or More Variables www. c k12 .org
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Guided Practice
1. Write the expression 2 × a in a more condensed form and then evaluate it for 3 = a .
2. If it costs $9.25 for a movie ticket, how much does it cost for 4 people to see a movie?
Solutions:
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Sample explanations for some of the practice exercises below are available by viewing the following video. Note
that there is not always a match between the number of the practice exercise in the video and the number of the
practice exercise listed in the following exercise set. However, the practice exercise is the same in both. CK-12 Ba
sic Algebra: Variable Expressions (12:26)
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In 1–4, write the expression in a more condensed form by leaving out the multiplication symbol.
1. 2 × 11 x
2. 1 . 35 · y
3. 3 ×
1
4
4.
1
4
· z
In 5–9, evaluate the expression.
5. 5 m + 7 when m = 3
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www. c k12 .org Chapter 1. Expressions, Equations, and Functions
6.
1
3
( c ) when c = 63
7. $8.15( h ) when h = 40
8. ( k - 11 ) ÷ 8 when k = 43
9. ( - 2 )
2
+ 3 ( j ) when j = - 3
In 10–17, evaluate the expression. Let a = - 3 , b = 2 , c = 5 , and d = - 4.
10. 2 a + 3 b
11. 4 c + d
12. 5 ac - 2 b
13.
2 a
c - d
14.
3 b
d
15.
a - 4 b
3 c + 2 d
16.
1
a + b
17.
ab
cd
In 18–25, evaluate the expression. Let x = - 1 , y = 2 , z = - 3 , and w = 4.
18. 8 x
3
19.
5 x
2
6 z 3
20. 3 z
2
- 5 w
2
21. x
2
- y
2
22.
z
3
+ w
3
z 3 - w 3
23. 2 x
2
- 3 x
2
+ 5 x - 4
24. 4 w
3
+ 3 w
2
- w + 2
25. 3 +
1
z
2
In 26–30, evaluate the expression in each real-life problem.
26. The measurement around the widest part of these holiday bulbs is called their circumference. The formula for
circumference is 2 ( r ) π , where π ≈ 3 . 14 and r is the radius of the circle. Suppose the radius is 1.25 inches.
Find the circumference.
27. The dimensions of a piece of notebook paper are 8.5 inches by 11 inches. Evaluate the writing area of the
paper. The formula for area is length × width.