17.equation; 18.equation; 19.expression;

20.equation;

Section 7.7 (pages 471–475)

1. (a)the amount (b) (c) 3. 5. 7. 12


2. 11.18.809 min 13.314.248 m per min 15.3.275 hr


3. 
   
   
   
   19. 21.8 mph 23.32 mph
   
   
   
   

25.165 mph 27.3 mph 29.18.5 mph 31. job per hr

33. 
    

    , or 35. 37. hr 39.3 hr

    
    


34. 
    

    hr 43. min 45. 47. 49.

    
    


35. 
    

Section 7.8 (pages 479–481)

1.direct 3.direct 5.inverse 7.inverse 9.inverse 11.direct
13.direct 15.inverse 17. (a)increases (b)decreases 19. 9

21. 250 23. 6 25. 21 27. 29. 31.$40.32 33. in.


22. mph 37. amps 39.20 lb 41.52.817


23. footcandles 45. 64 47. 49. 169

Chapter 7 Review Exercises (pages 487–490)

1. (a) (b) 2. (a)undefined (b) 1 3. 4.


2. 6.Set the denominator equal to 0 and solve the
   equation. Any solutions are values for which the rational expression is

undefined. 7. 8. 9. 10.

Answers may vary in Exercises 11 and 12. 11. ,

12.

13. 
    
    
    
    14. 2 15. 16. 17.
    
    
    
    


14. 
    
    
    
    19. 
        
        
        
        20. 
            
            
            
            21. 
                
            
            
            
            
        
        
        
        
    
    
    
    


15. 
    
    
    
    23. 
        
        
        
        24. 
            
            
            
            25. 
                
            
            
            
            
        
        
        
        
    
    
    
    


16. 
    
    
    
    27. 
        
        
        
        28. 
            
            
            
            29. 
                
            
            
            
            
        
        
        
        
    
    
    
    


17. 
    
    
    
    31. 
        
        
        
        32. 
            
        
        
        
        
    
    
    
    


18. 
    
    
    
    34. 
        
        
        
        35. 
            
        
        
        
        
    
    
    
    


19. 
    
    
    
    37. 
        
        
        
        38. 
            
            
            
            39. xw+ 1
                xw- 1
            
            
            
            
        
        
        
        
    
    
    
    

10

13

41 y- 32

y+ 3

• 13 p+ 33
  p 1 p- 221 p- 32

5 z- 16

z 1 z+ 621 z- 22

• k^2 - 6 k+ 3
  31 k+ 321 k- 32

7 a+ 6 b

1 a- 2 b 21 a+ 2 b 2

3116 - x 2

4 x^2

• 2 - 3 m
  6

28 + 11 y

y 17 +y 2

4 k- 45

k 1 k- 52

• 2
  p

15

x

4 b 1 b+ 22

1 b+ 321 b- 121 b+ 22

15 y

50 - 10 y

• 54
  18 - 6 x

15 a

10 a^4

1 x+ 321 x+ 121 x+ 42

108 y^4

3 z+ 1

z+ 3

p+ 5

p+ 1

y- 2

y- 3

3 a- 1

a+ 5

r+ 4

3

5

8

72

p

8 - 3 x

• 3 + 6 x

8 - 3 x

• 13 - 6 x 2


• 8 + 3 x ,
  3 - 6 x
  ,


• 18 - 3 x 2
  3 - 6 x

4 x- (^9) ,

• 2 x- 3

4 x- 9

• 12 x+ 32
  ,
  
  
  • 4 x+ 9
    2 x+ 3
  
  
  
  


• 14 x- 92
  2 x+ 3
  ,

2 p+ 5 q

5 p+q

• 
  

  12 x+ 32

  
  


• 
  

  (^12)
  b
  3 a
  kZ-5,-^23
  (^1181322) xZ 3 yZ 0
  142227 - 144
  10623 1212 in.^2
  (^165494223)
  k=xy
  k=
  y
  x
  2107 9111 E^403 F 536006
  225 hr 5115
  1
  8

  
  

• 
  

  1
  6

  
  

  1
  t
  1
  8
  t+
  1
  6
  t= 1
  1
  10
  500
  x- 10

  
  

  600
  x+ 10
  D
  R

  
  

  d
  r
  1386
  97
  12
  3
  12
  18
  5 +x
  6
  =^13
  3
  5 +x
  5 - 76
  t+ 2
  212 t+ 12
  (^00) 40. 41. or 42.

  
  

43. 
    
    
    
    44. 
        
        
        
        45. 
            
            
            
            46. 
                
                
                
                47. 
                    
                
                
                
                
            
            
            
            
        
        
        
        
    
    
    
    


44. 
    
    
    
    49. 
        
        
        
        50. 
            
            
            
            51. 52.10 mph
            
            
            
            
        
        
        
        
    
    
    
    


45. hr 54.2 hr 55.inverse 56.4 cm 57.


46. 
    
    
    
    59. 
        
        
        
        60. 
            
            
            
            61. 3 62.
            
            
            
            
        
        
        
        
    
    
    
    


47. or 64.


48. 66.150 km per hr 67. hr 68. 24 69. 4


49. 
    
    
    
    71. (a) (b) (c) 72. 73.If ,
        the divisor Ris equal to 0, and division by 0 is undefined.
    
    
    
    


50. 
    
    
    
    75. 
        
        
        
        76. 
            
            
            
            77. 78.We know that is not allowed, because PandRare undefined for
                . 79.Rate is equal to distance divided by time. Here, distance
                is 6 miles and time is minutes, so rate , which is the
                expression for P. 80. ,
            
            
            
            
        
        
        
        
    
    
    
    

Chapter 7 Test (pages 490–491)

[7.1]1. (a) (b)undefined 2. 3.(Answers may

vary.) , , , 4.

5. [7.2]6. 7. 8. 9.

[7.3]10. 11. 12.

13. [7.4]14. 2 15. 16. or
    17. [7.5]18.


14. [7.6]20. 21. 22. or

[7.7]23.3 mph 24. hr [7.8]25. 27

26.27 days

Chapters 1–7 Cumulative Review Exercises

(pages 491–492)

[1.2, 1.5, 1.6]1. 2 [2.3]2. [2.5]3. [2.6]4.

[2.8]5. [3.1, 3.2]6. (a) (b)

7. [5.4]8.

x

y

01

1

y = –x^2 + 1

x

y

2

0

1

y = –3x + 2

3 - 8,q 2 1 - 3, 0 2 1 0,- 42

b= E-^27 F

2 a

h

5176

D=d-k (^229)
F
D=
dF-k
E- F ,
1
E- 2 F
1
2 , 1F

• 2 - x
  4 +x

2 k

3 p

• m^2 + 7 m+ 2
  12 m+ 121 m- 521 m- 12

x^2 - x- 1

x- 3

• x^2 +x+ 1
  3 - x ,


• 14
  51 y+ 22

21

42 m- 84

240 p^2

64 p^3

150 p^512 r+ 321 r+ 221 r- 52

x- 5

3 - x

a- 1

a+ 4

3 k- 2

3 k+ 2

25

27

3 a+ 2

a- 1

• 3 x^2 y^3
  6 x- 5


• 2 x- 3

6 x- 5

• 12 x+ 32


• 6 x+ 5
  2 x+ 3


• 16 x- 52
  2 x+ 3

(^116) xZ-2, 4
5
2
6
5

6
1 x+ (^32) x+ 3
x=- 3

• 3

0

11 x+ 21

4 x

7

1 x+ 321 x+ (^12) x+ 1
x= 0
15
2 x

• 16 - 3 - 1 - 3,- 1

v=at+w 5111

t+ (^15) - 2, 3 6
12 +t 212 - t 2

• t- 1
  1 t+ 221 t- 22
  ,

z+ 7

1 z+ 121 z- 122

1

8 p^26

m+ 7

1 m- 121 m+ 12

36

(^35)
1
13
3
18
20
m= 15
4 +p^2 q
3 p^2
y=
4 x+ 5
3
t=
Ry
m
0 5 - 166 506 536
1 - r-t
1 +r+t
1 x- 521 x- 32 , x^2 - 8 x+ 15
1 q-p 22
pq
Answers to Selected Exercises A-19