Name: 
 

Chapter 4



Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 

Find the dimensions of the matrix.
mc001-1.jpg
a.
20 ´ 1
c.
4 ´ 5
b.
4 ´ 4
d.
5 ´ 5
 
 
Identify the given matrix element.
 

 2. 

mc002-1.jpg
mc002-2.jpg
a.
–1
b.
–8
c.
8
d.
–4
 

 3. 

mc003-1.jpg
mc003-2.jpg
a.
–5
b.
0
c.
7
d.
1
 

 4. 

In May, Bradley bought 48 styrofoam balls and decorated them as toy figurines. In June, he sold 19 figurines. In May, Lupe bought 44 styrofoam balls to decorate, and in June, she sold 21 figurines. Which matrix represents all of their May purchases and their June sales?
a.
mc004-1.jpg
c.
mc004-3.jpg
b.
mc004-2.jpg
d.
mc004-4.jpg
 

 5. 

State the dimensions of the matrix. Identify the indicated element.
mc005-1.jpg
a.
3 ´ 2, 0
c.
2 ´ 3, 4
b.
2 ´ 3, –7
d.
3 ´ 2, –7
 

 6. 

How many elements are in an m ´ n matrix?
a.
m + n
b.
mc006-1.jpg
c.
mc006-2.jpg
d.
mn
 

 7. 

A matrix contains 60 elements. Which of the following cannot equal the number of rows of the matrix?
a.
30
b.
60
c.
10
d.
18
 
 
Find the sum or difference.
 

 8. 

mc008-1.jpg
a.
mc008-2.jpg
c.
mc008-4.jpg
b.
mc008-3.jpg
d.
mc008-5.jpg
 

 9. 

mc009-1.jpg
a.
mc009-2.jpg
c.
mc009-4.jpg
b.
mc009-3.jpg
d.
mc009-5.jpg
 

 10. 

mc010-1.jpg
a.
mc010-2.jpg
c.
mc010-4.jpg
b.
mc010-3.jpg
d.
mc010-5.jpg
 

 11. 

mc011-1.jpg
a.
mc011-2.jpg
c.
mc011-4.jpg
b.
mc011-3.jpg
d.
mc011-5.jpg
 

 12. 

Suppose A and B are 2 ´ 5 matrices. Which of the following are the dimensions of the matrix A + B?
a.
2 ´ 5
b.
10 ´ 10
c.
7 ´ 1
d.
7 ´ 7
 
 
Use matrices A, B, and C. Find the sum or difference if you can.
nar003-1.jpg
 

 13. 

B + A
a.
mc013-1.jpg
c.
not possible
b.
mc013-2.jpg
d.
mc013-3.jpg
 

 14. 

mc014-1.jpg
a.
not possible
c.
mc014-3.jpg
b.
mc014-2.jpg
d.
mc014-4.jpg
 

 15. 

mc015-1.jpg
a.
mc015-2.jpg
c.
mc015-4.jpg
b.
mc015-3.jpg
d.
none of these
 
 
Find the values of the variables.
 

 16. 

mc016-1.jpg
a.
x = 2, y = 4
c.
x = 4, y = 2
b.
x = –1, y = 3
d.
x = 3, y = –1
 

 17. 

mc017-1.jpg
a.
t = –8, y = 4
c.
t = –2, y = 6
b.
t = 6, y = –8
d.
t = –8, y = 6
 

 18. 

mc018-1.jpg
a.
f = 4, k = 4, w = 11
c.
f = 4, k = –4, w = 11 or –11
b.
f = 4, k = 4, w = 11 or –11
d.
f = 4, k = 4, w = 121 or –121
 
 
Solve the matrix equation.
 

 19. 

mc019-1.jpg
a.
mc019-2.jpg
c.
mc019-4.jpg
b.
mc019-3.jpg
d.
mc019-5.jpg
 

 20. 

mc020-1.jpg
a.
mc020-2.jpg
c.
mc020-4.jpg
b.
mc020-3.jpg
d.
mc020-5.jpg
 

 21. 

mc021-1.jpg
a.
mc021-2.jpg
c.
mc021-4.jpg
b.
mc021-3.jpg
d.
mc021-5.jpg
 

 22. 

mc022-1.jpg
a.
mc022-2.jpg
b.
mc022-3.jpg
c.
mc022-4.jpg
d.
mc022-5.jpg
 

 23. 

mc023-1.jpg
a.
mc023-2.jpg
c.
mc023-4.jpg
b.
mc023-3.jpg
d.
mc023-5.jpg
 

 24. 

mc024-1.jpg
a.
mc024-2.jpg
c.
mc024-4.jpg
b.
mc024-3.jpg
d.
mc024-5.jpg
 
 
Find the product.
 

 25. 

mc025-1.jpg
a.
mc025-2.jpg
c.
mc025-4.jpg
b.
mc025-3.jpg
d.
mc025-5.jpg
 

 26. 

mc026-1.jpg
a.
mc026-2.jpg
c.
mc026-4.jpg
b.
mc026-3.jpg
d.
[12]
 

 27. 

mc027-1.jpg
a.
mc027-2.jpg
c.
mc027-4.jpg
b.
mc027-3.jpg
d.
mc027-5.jpg
 

 28. 

Find mc028-1.jpg.
mc028-2.jpg
a.
mc028-3.jpg
c.
mc028-5.jpg
b.
mc028-4.jpg
d.
mc028-6.jpg
 

 29. 

The Art Department and the Homecoming Committee at a local school are ordering supplies. The supplies they need are listed in the table.
 
Paint (bottles)
Brushes
Paper (reams)
Glue Sticks (boxes)
Tape (rolls)
Art Department
11
12
4
11
4
Homecoming Committee
10
14
7
17
7

A bottle of paint costs $4, a paint brush costs $2, a ream of colored paper costs $8, a box of glue sticks costs $3, and a roll of tape costs $2. Find the matrix that represents the total cost of supplies for each group.
a.
mc029-1.jpg
b.
mc029-2.jpg
c.
mc029-3.jpg
d.
mc029-4.jpg
 
 
Determine whether the product is defined or undefined. If defined, give the dimensions of the product matrix.
 

 30. 

mc030-1.jpg
a.
defined; 3 ´ 3
c.
defined; 2 ´ 3
b.
defined; 2 ´ 1
d.
undefined
 

 31. 

mc031-1.jpg
a.
defined; 2 ´ 2
c.
defined; 1 ´ 2
b.
defined; 2 ´ 1
d.
undefined
 
 
The points represent the vertices of a polygon. Use a matrix to find the coordinates of the image after the given transformation. Graph the preimage and the image.
 

 32. 

A(2, 3), B(–1, –4), and C(2, –2); a translation 1 unit left and 1 unit up
mc032-1.jpg
a.
A¢(1, 4), B¢(1, –1), C¢(–2, –3)
mc032-2.jpg
c.
A¢(1, 4), B¢(–2, –3), C¢(1, –1)
mc032-4.jpg
b.
A¢(1, 4), B¢(–2, 2), C¢(1, –1)
mc032-3.jpg
d.
A¢(1, –1), B¢(–2, –3), C¢(1, 4)
mc032-5.jpg
 

 33. 

W(2, 0), X(0, 2), Y(–1, 0), and Z(1, –2); a dilation of 2.5
mc033-1.jpg
a.
W(3, 0), X(0, 3), Y(–1.5, 0), and Z(1.5, –3)mc033-2.jpg
c.
W(3, 0), X(0, 5), Y(–1.5, 0), and Z(2.5, –5)mc033-4.jpg
b.
W(2, 0), X(0, 3), Y(–1, 0), and Z(2.5, –3)mc033-3.jpg
d.
W(5, 0), X(0, 5), Y(–2.5, 0), and Z(2.5, –5)mc033-5.jpg
 

 34. 

A(0, 0), B(–2, 3), and C(2, 1); a reflection across the y-axis
mc034-1.jpg
a.
mc034-2.jpg
c.
mc034-4.jpg
b.
mc034-3.jpg
d.
mc034-5.jpg
 

 35. 

A(0, 0), B(–1, 3), and C(2, 1); a rotation of 180º
mc035-1.jpg
a.
mc035-2.jpg
c.
mc035-4.jpg
b.
mc035-3.jpg
d.
mc035-5.jpg
 
 
Find the coordinates of the image after a reflection in the given line.
 

 36. 

mc036-1.jpg; y-axis
a.
mc036-2.jpg
c.
mc036-4.jpg
b.
mc036-3.jpg
d.
mc036-5.jpg
 

 37. 

mc037-1.jpg
a.
mc037-2.jpg
c.
mc037-4.jpg
b.
mc037-3.jpg
d.
mc037-5.jpg
 

 38. 

mc038-1.jpg-axis
a.
mc038-2.jpg
c.
mc038-4.jpg
b.
mc038-3.jpg
d.
mc038-5.jpg
 

 39. 

Find the coordinates of the image after the given rotation.
mc039-1.jpgmc039-2.jpg
a.
mc039-3.jpg
c.
mc039-5.jpg
b.
mc039-4.jpg
d.
mc039-6.jpg
 
 
Which of the following is the multiplicative inverse of the given matrix?
 

 40. 

mc040-1.jpg
a.
mc040-2.jpg
b.
mc040-3.jpg
c.
mc040-4.jpg
d.
mc040-5.jpg
 

 41. 

mc041-1.jpg
a.
mc041-2.jpg
c.
mc041-4.jpg
b.
mc041-3.jpg
d.
mc041-5.jpg
 
 
Evaluate the determinant of the matrix.
 

 42. 

mc042-1.jpg
a.
17
b.
1
c.
–1
d.
–17
 

 43. 

mc043-1.jpg
a.
0
b.
mc043-2.jpg
c.
mc043-3.jpg
d.
mc043-4.jpg
 

 44. 

mc044-1.jpg
a.
–24
b.
40
c.
–32
d.
–40
 
 
Determine whether the matrix has an inverse. If an inverse exists, find it.
 

 45. 

mc045-1.jpg
a.
mc045-2.jpg
c.
does not exist
b.
mc045-3.jpg
d.
mc045-4.jpg
 

 46. 

mc046-1.jpg
a.
mc046-2.jpg
c.
does not exist
b.
mc046-3.jpg
d.
mc046-4.jpg
 

 47. 

mc047-1.jpg
a.
mc047-2.jpg
c.
mc047-4.jpg
b.
mc047-3.jpg
d.
mc047-5.jpg
 
 
Evaluate the determinant.
 

 48. 

mc048-1.jpg
a.
mc048-2.jpg
b.
mc048-3.jpg
c.
mc048-4.jpg
d.
mc048-5.jpg
 

 49. 

mc049-1.jpg
a.
–58
b.
58
c.
–102
d.
102
 

 50. 

mc050-1.jpg
a.
35
b.
–1
c.
–70
d.
0
 
 
Assign each letter and a blank space to a number as shown by the alphabet table below:
0 = _
1 = A
2 = B
3 = C
4 = D
5 = E
6 = F
7 = G
8 = H
9 = I
10 = J
11 = K
12 = L
13 = M
14 = N
15 = O
16 = P
17 = Q
18 = R
19 = S
20 = T
21 = U
22 = V
23 = W
24 = X
25 = Y
26 = Z
 

 51. 

Use mc051-1.jpg to encode the phrase “FIT AS A FIDDLE”.
a.
mc051-2.jpg
c.
mc051-4.jpg
b.
mc051-3.jpg
d.
mc051-5.jpg
 

 52. 

The matrix mc052-1.jpg was used to encode to mc052-2.jpg. Find mc052-3.jpgand use it to decode the matrix.
a.
IN BROAD DAYLIGHT
c.
GRIND TO A HALT
b.
RUN LIKE THE WIND
d.
LEAPS AND BOUNDS
 

 53. 

Write the system mc053-1.jpgas a matrix equation. Then identify the coefficient matrix, the variable matrix, and the constant matrix.
a.
mc053-2.jpg
variable matrix:mc053-3.jpg
coefficient matrix:mc053-4.jpg
constant matrix:mc053-5.jpg
c.
mc053-10.jpg
variable matrix:mc053-11.jpg
constant matrix:mc053-12.jpg
coefficient matrix:mc053-13.jpg
b.
mc053-6.jpg
coefficient matrix:mc053-7.jpg
constant matrix:mc053-8.jpg
variable matrix:mc053-9.jpg
d.
mc053-14.jpg
coefficient matrix:mc053-15.jpg
variable matrix:mc053-16.jpg
constant matrix:mc053-17.jpg
 

 54. 

Use an augmented matrix to solve the system mc054-1.jpg.
a.
mc054-2.jpg
b.
no solution
c.
mc054-3.jpg
d.
mc054-4.jpg
 

 55. 

Write an augmented matrix to represent the system.
mc055-1.jpg
a.
mc055-2.jpg
c.
mc055-4.jpg
b.
mc055-3.jpg
d.
mc055-5.jpg
 
 
Use Cramer’s Rule to solve the system.
 

 56. 

mc056-1.jpg
a.
mc056-2.jpg
b.
no solution
c.
mc056-3.jpg
d.
mc056-4.jpg
 

 57. 

mc057-1.jpg.
a.
(3, 5, 4)
c.
(–2, –25, 10)
b.
(3, –5, –4)
d.
(–3, –5, –4)
 

 58. 

mc058-1.jpg
a.
mc058-2.jpg
b.
no solution
c.
mc058-3.jpg
d.
mc058-4.jpg
 
 
Solve the system.
 

 59. 

mc059-1.jpg
a.
(–3, –2, –4)
c.
(3, –2, –4)
b.
(11, 17, 0)
d.
(–3, 2, 4)
 

 60. 

mc060-1.jpg
a.
(5, –4, 1)
c.
(5, 4, –1)
b.
(–5, –36, –13)
d.
(–5, –4, 1)
 

 61. 

mc061-1.jpg
a.
no unique solution
c.
(2, 1, 5)
b.
(2, 0, –5)
d.
(–2, 0, –5)
 

 62. 

mc062-1.jpg
a.
(19, 14, –2, –7)
c.
(3, 4, –3, 0)
b.
(3, –4, –3, 0)
d.
(–3, 4, 3, –1)
 

 63. 

mc063-1.jpg
a.
mc063-2.jpg
b.
mc063-3.jpg
c.
no solution
d.
mc063-4.jpg
 

 64. 

A gem store sells beads made of amber and quartz. For 4 amber beads and 4 quartz beads, the cost is $46.00. For 1 amber bead and 3 quartz beads, the cost is $14.50. Find the price of each type of bead.
a.
amber $10.00, quartz $1.50
c.
amber $10.25, quartz $1.75
b.
amber $9.75, quartz $1.25
d.
amber $1.50, quartz $10.00
 
 
Write the coefficient matrix for the system. Use it to determine whether the system has a unique solution.
 

 65. 

mc065-1.jpg
a.
mc065-2.jpg; yes
c.
mc065-4.jpg; no
b.
mc065-3.jpg; no
d.
mc065-5.jpg; yes
 

 66. 

mc066-1.jpg
a.
mc066-2.jpg; no
c.
mc066-4.jpg; yes
b.
mc066-3.jpg; yes
d.
mc066-5.jpg; no
 

 67. 

Write a system of equations for the augmented matrix mc067-1.jpg.
a.
mc067-2.jpg
c.
mc067-4.jpg
b.
mc067-3.jpg
d.
mc067-5.jpg
 

 68. 

A graphics designer has a star-shaped figure with vertices whose coordinates are represented by the matrix below. Her customer wants the figure increased in size by a factor of 1.5. Find the coordinates of the vertices of the enlargement.
mc068-1.jpg
a.
mc068-2.jpg
c.
mc068-4.jpg
b.
mc068-3.jpg
d.
mc068-5.jpg
 

Short Answer
 

 69. 

This table shows data on heating oil use for two years in three adjacent buildings on Spring Street.
Heating Oil Use
Number of Gallons Used
Address
2002
2003
152 Spring St.
1215
1093
154 Spring St.
982
975
156 Spring St.
1562
1437

a.Write a matrix H to represent the data.
b.Find element sa069-1.jpg. What does this element represent?
 

 70. 

Verify that the matrix has no inverse.
sa070-1.jpg
 

 71. 

Consider the matrix sa071-1.jpg
a.Find and simplify an expression for det A.
b.Use your answer to part (a) to find det A for a = –2.
 

 72. 

The graph shows the populations of two towns.
sa072-1.jpg
a.Show the data in a matrix.
b.What doessa072-2.jpg represent?
 

 73. 

Three friends recorded they amount of time each spent exercising and sleeping over the course of a week.
 
Sleep (hours)
Exercise (hours)
Maria
56
7
Validamir
60
5
Lee
63
10

a.Put the information into two matrices. Label each matrix.
b.Find the difference between total hours sleeping and exercising for each person.
 

Essay
 

 74. 

es074-1.jpg
a.Write the vertices of the figure above in a matrix.
b.Graph the figure and its image after a reflection in the x-axis.
c.Do any of the vertices of the preimage have the same coordinates as the vertices of the reflection? Explain.
d.Give the coordinates of a point of the preimage that is also a point of the reflection.
 

 75. 

The following tables show car and SUV sales for a dealership in 1990 and 2000. The months shown represent the end of each quarter.

Sales in 1990
 
March
June
September
December
SUVs
60
33
26
77
Cars
128
201
179
114

Sales in 2000
 
March
June
September
December
SUVs
110
66
80
118
Cars
122
188
176
99

a.Organize the information into two 2 x 4 matrices, A (1990) and B (2000).
b.Calculate the matrix that shows the change in sales from 1990 to 2000.
c.For which type of vehicle did sales increase? Explain.
 

 76. 

Mr. Gabrielli teaches French and Spanish. This chart shows the mean scores on the vocabulary sections and comprehension sections of tests for two different classes of each language.
Mean Scores
  
Class 1
Class 2
Vocabulary
French
Spanish
32
41
39
35
Comprehension
French
Spanish
35
39
42
43

a.Write matrices for the vocabulary (V) scores and the comprehension (C) scores.
b.Write the matrix for the combined scores, V + C.
c.Which class had the higher combined test scores, and for which language?
 

Other
 

 77. 

What does the expression ot077-1.jpg represent if A is a matrix? If ot077-2.jpg exists, what can you say about the dimensions of A? Explain.
 

 78. 

Write a system of three equations that has a unique solution of (1, 2, 3).
 

 79. 

The matrix ot079-1.jpg has no inverse. Explain how you can determine the value of x. Then find x.
 

 80. 

Determine whether the following statement is always, sometimes or never true.Explain your answer.
Given two different n x n matrices A and B, AB = BA.
 

 81. 

A triangle has vertices A(1, 1), B(3, 2), and C(-2, 4).
a.Transform the triangle by multiplying ot081-1.jpg.
b.Graph the preimage and image.
c.Describe the transformation.
 



 
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