Beginning Algebra, 11th Edition

Answers to Selected Exercises A-7

43. 
    
    
    
    45. 
        
        
        
        47. 
            
        
        
        
        
    
    
    
    


44. 
    
    
    
    51. 
        
        
        
        53. 
            
        
        
        
        
    
    
    
    

In Exercises 55– 61, descriptions may vary.
55.The graph is a line with x-intercept and y-intercept
57.The graph is a vertical line with x-intercept.
59.The graph is a horizontal line with y-intercept
61.The graph has x- and y-intercepts. It passes through the points
and.

63. 
    
    
    
    65. 
        
    
    
    
    


64. (a)121 lb; 143 lb; 176 lb (b)
    (c) (d)68 in.; 68 in.


65. (a)$62.50; $100 (b) 200 (c)
    (d)


66. (a)$30,000 (b)$15,000 (c)$5000 (d)After 5 yr, the SUV
    has a value of $5000. 73. (a)2000: $73 billion; 2004: $85 billion;
    2006: $91 billion (b)2000: $74 billion; 2004: $86 billion;
    2006: $91 billion (c)The values are quite close. 75. 77.

Section 3.3 (pages 206–210)

1. 4 3. 5. 0 7.Rise is the vertical change between two differ-
   ent points on a line. Run is the horizontal change between two different
   points on a line. 9. (a)C (b)A (c)D (d)B

In Exercises 11 and 13, sketches will vary.
11.The line must fall from left to right. 13.The line must be vertical.

15. (a)negative (b)zero 17. (a)positive (b)negative


16. (a)zero (b)negative 21. 23. 25.Because he found
    the difference 3 - 5 =- 2 in the numerator, he should have subtracted

278 -^23

• (^12)
  1
  2
  2
  3
  x
  y
  50
  100
  150
  200
  050 100 150 200
  y = 0.75x + 25
  Cost (in dollars)
  Number of Posters
  1 50, 62.50 2 , 1 100, 100 2 , 1 200, 175 2
  x
  y
  y = 5.5x – 220
  60 6468 72
  120
  0
  130
  140
  150
  160
  170
  180
  Weight (in lb)
  Height (in in.)
  1 62, 121 2 , 1 66, 143 2 , 1 72, 176 2
  x
  y
  0
  (–3, –3)(–3, –3)
  (0, –3)(0, –3)
  (4, –3)(4, –3)
  y=- 3
  x
  y
  0
  (3, 5)
  (3, 0)
  (3, –3)
  x= 3
  1 2, 1 2 1 4, 2 2
  1 0, 0 2
  1 0, - 22.
  1 11, 0 2
  1 - 3, 0 2 1 0, 9 2.
  x
  x + 2 = 8
  y
  0
  6
  x 0
  y
  0
  –5–3y = 15
  x
  y
  0
  x + 2 = 0
  x
  y
  0
  y = – 1
  x
  y
  0
  1
  –6
  y = –6x
  x
  y
  0
  2
  4
  y – 2x = 0
  in the same order in the denominator to get The correct
  slope is 27. 29. 31. 0 33. 35.undefined

37. 
    
    
    
    39. 
        
        
        
        41. 5 43. 45. 47. 49. 0 51.undefined
        
        
        
        
    
    
    
    


38. ; 55.A 57. ; ; parallel 59. ; ; neither


39. ; ; perpendicular 63.5; ; neither 65.232 thousand, or 232,000
    66.positive; increased 67.232,000 students 68.
    69.negative; decreased 70.0.95 students per computer


40. (a) (b) 174 (c)Music purchases
    increased by 696 million units in 4 yr, or 174 million units per year.
    73.0.4 75. 77. 79.


41. 
    

Section 3.4 (pages 218–222)

1.E 3.B 5.C 7.A 9.slope: ; y-intercept:

11.slope: ; y-intercept: 13.slope: ; y-intercept:

15. 
    
    
    
    17. 
        
        
        
        19. 
            
        
        
        
        
    
    
    
    


16. 
    
    
    
    23. 
        
        
        
        25. 
            
            
            
            27. 
                
            
            
            
            
        
        
        
        
    
    
    
    


17. 
    
    
    
    31. 
        
        
        
        33. 
            
        
        
        
        
    
    
    
    


18. 
    
    
    
    37. 
        
        
        
        39. 
            
        
        
        
        
    
    
    
    


19. 
    
    
    
    43. 
        
        
        
        45. 
            
        
        
        
        
    
    
    
    


20. 49.the y-axis 51.
    53. 55.
    57. 59.
    61. 63.A, B, D


21. (a) (b) 67. (a)
    (b) 69. (a) (b)


22. (a) (b) 73.


23. 
    
    
    
    77. 
        
        
        
        79. (a)$400 (b)$0.25
            (c) (d)$425 (e) 1500
        
        
        
        
    
    
    
    


24. (a)
    (b)yes (c) (d)$2549


25. 
    
    
    
    85. 
        
    
    
    
    


26. 
    
    
    
    89. 00 55
    
    
    
    

3 5, q 2

–3–3 00

1 - 3, q 2

y= 15 x-29,978 y=- 3 x+ 6

y= 94 x+ 1985

x

y

0124

2000

2100

2200

2300

2400

2500

35

Ye a r

Cost (in dollars)

1 1, 2079 2 , 1 2, 2182 2 , 1 3, 2272 2 , 1 4, 2361 2 , 1 5, 2402 2

y=0.25x+ 400

y= 4 x- 5 y= 43 x- 29

y=- 31 x+^2293 x+ 9 y= 22 y=- 2 x- 3

x- 2 y=- 4 y=-^35 x-^1153 x+ 5 y=- 11

y=x+ 6 x-y=- 6 y= 21 x+ 2

y=-^45 x+^95

y= 43 x+ 4 y= 32 x+^193

y=- 4 x- 1 y=x- 6

y= 2 x- 7

x

y

(2, 4)

0

x

y

(–2, 3)

0

(0, 0)

(1, –2)

x

y

x^0

y

(–1, 4) (4, 6)

0

x

y

(1, –5)

0

(6, –7)

x

y

(0, 1)

(1, 5)

xx 0

yy

00

(5, 0)(5, 0)

(0, –4)(0, –4)

4 x – 5y = 20

xx

yy

00

(0, –5)(0, –5)

22 x + yx + y = –5 = –5

(1, –7)(1, –7)

xx

yy

00

(0, 4)(0, 4) (3, 3)(3, 3)

yy = – = – 3113 xx + 4 + 4

x

y

(0, 2)

(1, 5)

0

y = 3x + 2

y= 4 x- 3 y=-x- 7 y= 3 x= 0

y= 3 x- 3 y=-x+ 3 y=- 21 x+ 2

• 1 1 0, 9 2 15 A0, - 103 B

(^521) 0, - 42
y= 2 x- 16
1 0, 4 2 y=- 25 x+ 3 y=^103 x- 10
1 2004, 817 2 , 1 2008, 1513 2

• 0.95

1

• 
  

  (^5)
  2
  3
  3
  2

  
  


• 
  

  331 - 52 - 25 98 - 34

  
  

3

2

3

2

1

• 
  

  (^4)
  1
  2
  1
  4

  
  


• 
  
  
  
  • (^23) = 32. 45 23 - 3
  
  
  
  


• 
  

  1 - 2 =-3.