Answers A-3
86. (A) p = 0.0005x - 1.7 (B) p = -0.0005x + 7.8 (C) (9,500, 3.05)
(D) p
x
3.20
3.00
2.80
9,800
Supply
Demand
9,2000
Dollars
Millions of Bushels
Equilibrium point
47. x = 4, y = - 3 48. x = - 5; y = 6 49. x = -1.5, y = -3.5
50. x = 2.6; y = 3.8 51. y = 5x - 15 52. y = 4x + 6
53. y = -2x + 7 54. y = - 10x + 15 55. y = 1
3 x - 20
3
56. y = 2
7 x - 1 57. y = - 3.2x + 30.86 58. y = 0.9x + 4.63
59. (A) m = 2
3 (B) - 2x + 3y = 11 (C) y = 2
3 x + 11
3
60. (A) m = 3
2 (B) 3x - 2y = - 1 (C) y = 3
2 x + 1
2
61. (A) m = - 5
4 (B) 5x + 4y = - 14 (C) y = - 5
4 x - 7
2
62. (A) m = - 4
5 (B) 4x + 5y = 23 (C) y = - 4
5 x + 23
5
63. (A) Not defined (B) x = 5 (C) None 65. (A) m = 0 (B) y = 5
(C) y = 5 66. (A) Not defined (B) x = 2 (C) None 67. The graphs
have the same y int., (0, 2). 68. The graphs have the same slope, -0.5.
69. C = 124 + 0.12x; 1,050 donuts 70. C = 1,200 + 45x; 80 picnic tables
71. (A) C = 75x + 1,647 (B) C
x
5,000
10,000
15,000
0 05 051001
(C) The y int., $1,647,
is the fixed cost
and the slope,
$75, is the cost
per club.
72. (A) C = 39x + 1,905 (B) C
x
6,000
4,000
2,000
100200 60
(C) The y int., $1,905,
is the fixed cost,
and the slope,
$39, is the cost
per racket.
73. (A) R = 1.4C - 7 (B) $137 74. (A) R = 1.5C + 3 (B) $158
75. (A) V = - 7,500t + 157,000 (B) $112,000 (C) During the 12th year
(D) V
t
$40,000
$80,000
$120,000
100 20
Years
(6, 112,000)
(11.6, 70,000)
76. (A) V = - 6,800t + 224,000
(B) $156,000 (C) During the 19th year
(D) V
t
$40,000
$80,000
$120,000
$160,000
$200,000
100 20
Years
(10, 156,000)
(18.24, 100,000)
77. (A) T = - 1.84x + 212 (B) 205.56°F (C) 6,522 ft
(D) T
x
220
180
190
200
210
20100
Temperature (8F)
Thousands of Feet
(3.5, 205.56)
(6.522, 200)
78. (A) T = 14x - 206.6 (B) 227.4°F
(C) 28.97 inHg (D) T
x
225
215
205
195
185
3228 300
Temperature (8F)
Barometric Pressure
(inHg)
(31, 227.4)
(28.97, 199)
79. (A) T = 70 - 3.6A (B) 10,000 ft 80. (A) T = 3.2A
