MSM07G6_RESBK_Ch02_003-010.pe
1/2/06
1:45 PM
Page 5
Name
LESSON
Date
Class
Practice C
2-1 Variables and Expressions
Evaluate each expression to find the missing values in the tables.
1.
n
n 15
30
105
2
5
1
7
n
n 17
34
51
72
43
117
75
15
3.
55
26
100
2.
n
3n 23
3
1
16
22
79
8
10
29
4.
l
w
lw
5
3
6
3
7
3
8
3
15
18
21
24
Evaluate each expression for the given value of the variable.
5. 5x 2 for x 4
6. 63 8z for z 7
22
7
64
8. ᎏvᎏ 11 for v 4
11. 48 n for n 3
88
9. 19w for w 5
5
63
12. x x x for x 15
45
13. 16 n 2 for n 3
25
14. What is the next expression in the
following pattern: 4n; 8n; 16n?
15. What is the next expression in the
pattern x 27; x 24; x 21?
x 18
32n
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
10. 98 5q for q 7
95
16
7. 176 p for p 2
5
Holt Mathematics
MSM07G6_RESBK_Ch02_069-086.pe
1/4/06
11:45 AM
Page 69
Practice B
2-1 Variables and Expressions
Practice A
2-1 Variables and Expressions
LESSON
LESSON
Evaluate each expression to find the missing values in the tables.
Circle the letter of the correct answer.
1.
1. Which of the following is an algebraic
expression?
A 4 13
B 10 • (3 2)
C 15 5
D 9n
嘷
2. What is the variable in the
expression (16 a) • 5 4?
F 16
Ga
嘷
H 5
J n
3. Which of these expressions is a way
to rewrite the algebraic expression
n 3?
4. Which of these expressions is
not a way to rewrite the algebraic
expression n • 4?
F n(4)
Gn•4
n
A ᎏ3ᎏ
嘷
B n•3
C 3n
4
H ᎏnᎏ
嘷
3
D ᎏnᎏ
J 4n
6.
5.
2
n
n3
n
n•2
1
4
2
8
2
5
8
10
13
3
12
20
28
32
5
7
10
5
7
8
2
3
Holt Mathematics
30
105
2
5
1
7
n
n 17
34
51
72
43
117
75
15
3.
55
26
100
n
n•7
n
24 n
8
56
2
12
9
6
12
63
77
84
8
4
6
3
n
n 15
n
n • 23
35
50
20
35
100
7
56
32
80
104
25 n
n
18
4.
4
6.
4
10
13
8. Shawn evaluated the algebraic
expression x 4 for x 12 and
gave an answer of 8. What was his
error? What is the correct answer?
55 will be the constant, and the
He used subtraction instead of
number of hours will be the
division. The correct answer
variable.
is 3.
4
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Mathematics
Reteach
2-1 Variables and Expressions
LESSON
A variable is a letter or a symbol that stands for a number that can
change. A constant is an amount that does not change.
Evaluate each expression to find the missing values in the tables.
n 15
9
20
7
16
7. A car is traveling at a speed of
55 miles per hour. You want to write
an algebraic expression to show how
far the car will travel in a certain
number of hours. What will be your
constant? your variable?
Practice C
2-1 Variables and Expressions
n
5
35
73
86
99
85
LESSON
1.
5
9
20
7
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
20
5
8. If x 2, what is the value of the
expression 9 x?
7. If x 3, what is the value of the
expression 6 x?
71
11
Evaluate each expression to find the missing values in the tables.
5.
n 82
7
22
3.
2.
n
2.
n
3n 23
3
1
16
22
79
8
10
29
4.
A mathematical phrase that contains at least one variable is an
algebraic expression. In the algebraic expression x 5, x is a
variable and 5 is a constant.
When you evaluate an algebraic expression, substitute a number for
the variable and then find the value.
l
w
lw
5
3
6
3
7
3
8
3
15
18
21
24
To evaluate the algebraic expression m 8 for m 12, first replace
the variable m in the expression with 12.
m8
12 8
Then find the value of the expression.
12 8 4
The value of m 8 is 4 when m 12.
Evaluate each expression for the given value of the variable.
1. x 5, for x 6
Evaluate each expression for the given value of the variable.
5. 5x 2 for x 4
6. 63 8z for z 7
22
64
8. ᎏvᎏ 11 for v 4
7
5
11. 48 n for n 3
10. 98 5q for q 7
95
63
12. x x x for x 15
16
45
13. 16 n 2 for n 3
25
14. What is the next expression in the
following pattern: 4n; 8n; 16n?
x
4x
3
12
4
䡵
5.
x 18
5
Copyright © by Holt, Rinehart and Winston.
8
5
䡵
Think: x 3, so 4x 4 • 3 12
Think: x 4, so 4x 4 • 4 16
Think: x 5, so 4x 4 • 5 20
Holt Mathematics
x7
y
y2
3
10
9
5
12
14
10
7
8
12
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
69
6.
x
7
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
4. w 7, for w 15
6
Evaluate each expression to find the missing values in the tables.
15. What is the next expression in the
pattern x 27; x 24; x 21?
32n
3. z 4, for z 24
15
To find the missing values in a table, use the given values of the variable.
88
9. 19w for w 5
2. 3p, for p 5
11
7. 176 p for p 2
14
6
Holt Mathematics
Holt Mathematics