Intermediate Algebra (11th edition)

33. (a)undefined (b)vertical 35. (a) (b)falls 37. 6 39.


34. 43.undefined 45. 47.


35. 4 51.undefined


36. 0 55. 0 57.


37. 
    
    
    
    61. 
        
        
        
        63. 
            
        
        
        
        
    
    
    
    

x

y

0 2

(2, –5)

x

y

0

(0, 1)

(–1, –2)

x

y

0

(0, –2) (3, – 4)

x

y

0

(–2, 3)

xx (– 4, 2)

yy

00

22 y y = 3= 3

x

y

0

–5

y = –5

x

y

0 3

x – 3 = 0

x

y

0

1

4

y = 4x

x

y

0

2

–5

5 x – 2y = 10

5

2

x

y

0

2

4

x + 2y = 4

-^52 -^12

• 1 - 3

A-6 Answers to Selected Exercises

27. (a) ; 5; ; 1

(b)

x + 2y = 5

0

y

(5, 0)x

(1, 2)

(0,^52 )

(2,^32 )

3

2

5

2 29. (a) ; 5; ;

(b)

x

y

4 x – 5y = 20

0

(5, 0)

(0, – 4) ( (^5) , –3)
4
(2, –^125 )
5

• 
  

  4
  12

  
  


• 
  

  (^45)

  
  

31. (a)3; 1;
    (b)

xx

yy

00

(0, 3)(0, 3)

(1, 1)(1, 1)

(2, –1)(2, –1)

(3, –3)(3, –3)

y = –2x + 3

• 1; - 3 33. (a) 1 (b) 2 (c)For every
  increase in xby 1 unit, yincreases
  by 2 units.

35. ;

x

y

0 6

4

2 x + 3y = 12

1 6, 0 21 0, 4 2 39. ;

x

y

0

–2

5 x + 6y = –1 0

-^53

1 - 2, 0 (^2) A0, -^53 B

41. ;

x

y

0

(^2246810)
7
3
2
3
21

-^2

x – 3y = 7

A^212 , 0B A0, - 37 B 45. ; none

02

y

x

x = 2

1 2, 0 2

37. ;

x – 3y = 6

0

–2

6

y

x

1 6, 0 21 0, - 22

43.none;

0

5

y

x

y = 5

1 0, 5 2

47. ; none

x

y

–4 0

x + 4 = 0

1 - 4, 0 2 49.none;

x

y

0

y + 2 = 0

1 0, - 22 51. ;

x

y

0

–1

5

x + 5y = 0

1 0, 0 21 0, 0 2

53. ;

x

y

03

2

2 x = 3y

1 0, 0 21 0, 0 2 55. ;

x

y

0 2

-^23 y = x

–3

1 0, 0 21 0, 0 2 57.

59.

61.

63.

65. 1 1, 1 2

1 2.1, 0.9 2

A0,^112 B

A^92 , -^32 B

1 - 5, - 12

67. 
    
    
    
    69. 
        
        
        
        71. 73.B
        
        
        
        
    
    
    
    

75.Window B is more useful because it shows the intercepts.
77.

–10

–10 10

10

y = –2.5x – 5

A- 125 , 285 B Q^1 11, -^42 Q^1 4.5, 0.75^2

79. 2 81. 0


80. 
    

85.y=

12 - 3 x

4

, or y=-

3

4

x+ 3

y= 4 x- 10

Section 3.2 (pages 155 –161)

1.A, B, D, G 3.5 ft 5. (a)C (b)A (c)D (d)B 7. 2
9.undefined 11. 1 13. 15. 2 17. 19. 0 21.undefined

23. (a)B (b)C (c)A (d)D 25. (a) 8 (b)rises 27. (a)
    (b)rises 29. (a) 0 (b)horizontal 31. (a)-^12 (b)falls

5

6

5

• (^12)

65. 
    

    x
    y
    –3 0
    (–3, 1) 1

    
    


66. 
    

    69.parallel 71.perpendicular
    73.neither 75.parallel 77.neither
    79.perpendicular 81. per yr; The value
    of the machine is decreasing $4000 each year
    during these years.

    
    
    
    
    • $4000
      -^49 ;^94
    
    
    
    

83.0% per yr (or no change); The percent of pay raise is not changing—

it is 3% each year during these years. 85.19.5 ft 87. (a)21.2

(b)The number of subscribers increased by an average of 21.2 million

each year from 2005 to 2008. 89. (a) 5 theaters per yr (b)The

negative slope means that the number of drive-in theaters decreased by an

average of 5 each year from 2000 to 2007. 91.$1371.67 million per yr;

Sales of plasma TVs increased by an average of $1371.67 million each

year from 2003 to 2006. 93.Since the slopes of both pairs of opposite

sides are equal, the figure is a parallelogram. 95. 96. 97.

98. is true. 99.collinear 100.not collinear


99. 
    
    
    
    103. 
         
         
         
         105. 
              
         
         
         
         
    
    
    
    

Connections (page 169) 1. 2. 3. 4.

Section 3.3 (pages 169 –174)

1.A 3.A 5. 7.A 9.C 11.H 13.B

15. 
    
    
    
    17. 
        
        
        
        19. 
            
        
        
        
        
    
    
    
    


16. 
    
    
    
    23. 
        
        
        
        25. 
            
        
        
        
        
    
    
    
    


17. (a) (b) 1 (c) (d)


18. (a) (b) (c) (d)

x

y

0

(0, 6)

(5, 0)

6 x + 5y = 30

y=- 56 x + 6 - 56 1 0, 6 2

x

y

–4 0

(1, 5)

(0, 4)

• x + y = 4

y=x+ 4 1 0, 4 2

y=^25 x+ 5 y= 32 x+ 1 y=-x- 2

y= 5 x+ 15 y=-^23 x+^45 y=x- 1

3 x+y= 10

506 516 5 - 0.5 6 536

y=- 23 x+ 4 y= 4 x+ 14 x+ 2 y=- 4

1

3 =

1

3 =

1

3

1

3

1

3

1

3

•