Intermediate Algebra (11th edition)

52.The company should use 100 workers and manufacture 3000 units to

achieve the least possible cost. 53. 55.

Section 3.5 (pages 187–189)

1.Answers will vary. A function is a set of ordered pairs in which
each first component corresponds to exactly one second component.

For example, is a function.
3.independent variable

In Exercises 5 and 7, answers will vary.

5. 
   
   
   
   7. 
      
   
   
   
   

9.function; domain: 5, 3, 4, 7 ; range: 1, 2, 9, 6 11.not a
function; domain: 2, 0 ; range: 4, 2, 5 13.function; domain:

range: 1, 7 15.not a function; domain: ;
range: 17.function; domain: ;

range: 19.not a function; domain: ; range:
21.function; domain: range: 23.function;

domain: range: 2, 3 25.function; domain:
range: 27.not a function; domain: ; range:

29.function; domain: range: 31.not a function;
domain: range: 33.function;

35.function; 37.function; 39.not a function;
41.not a function; 43.function;

45.function; 47.function; 49.function;
51.function; 53.function;

55.function; 57. (a)yes (b)domain: 2004,
2005, 2006, 2007, 2008 ; range: 42.3, 42.8, 43.7, 43.8 (c)Answers

will vary. Two possible answers are 2005, 42.3 and 2008, 43.8.

59. 
    
    
    
    61. 1 63.
    
    
    
    

Section 3.6 (pages 194 –197)

1.B 3. 4 5. 7. 3 9.2.75 11. 13.

15. 
    
    
    
    17. 
        
        
        
        19. 
            
            
            
            21. 
                
            
            
            
            
        
        
        
        
    
    
    
    


16. (a) (b) 25. (a) 2 (b) 3 27. (a) 15 (b) 10


17. (a) 4 (b) 1 31. (a) 3 (b) 33. (a) (b) 2


18. (a) 2 (b) 0 (c) 37. (a) (b)


19. (a) (b) 41. (a) (b)
    43.line; ; ; ;

45.domain: ;
range: 1 - q, q 2

1 - q, q 2

• 2;- 2 x+ 4 - 23 - 2

4

ƒ 1 x 2 = 3

4

3 x-

8

ƒ 1 x 2 = 3 - 2 x^2 - (^153)

• 1 ƒ 1 x 2 =- 31 x+ 4 3
  
  
  • 3 - 3
  
  
  
  


• 1 - 1


• 3 x- 2 - p^2 + 4 p+ 1 - 3 x- 3 h+ 4 - 9


• 11 - 3 p+ 4 3 x+ 4


• 9 y= 21 x-^74

1 2 1 2

6 5 6

1 - q, 0 2 ́ 1 0, q 2 5

1 - q, 0 2 ́ 1 0, q 2 1 - q, 4 2 ́ 1 4, q 2

3 3, q 2 C-^12 , qB 1 - q, q 2

3 0, q 2 1 - q, q 2 3 0, q 2

1 - q, q 2 1 - q, q 2

3 - 4, 4 4 ; 3 - 3, 3 4 1 - q, q 2

1 - q, q 2 ; 1 - q, 4 4

1 - q, q 2 1 - q, 0 4 1 - q, q 2

5 - 2, 0, 3 6 ; 5 6 1 - q, q 2 ;

5 4, 2, 0, - 26 ; 5 - 36

5 1, 7, 20 6 516 5 5, 2, -1, - 46

5 1, -1, 0, 4, - 46 5 2, 5, 11, 17, 3 6

5 - 3, 4, - 26 ; 5 6 5 1, 0, 2 6

5 6 5 6

5 6 5 6

x

y

0 2

2

51 0, 1 2 , 1 1, 2 2 , 1 2, 3 2 , 1 3, 4 26

3 0, q 2 1 - q, 1 2 ́ 1 1, q 2

A-8 Answers to Selected Exercises

xy

34

31

20

• 
  


• 
  
  
  
  • 
    
  
  
  
  

5

0

y

x

f(x) = –2x + 5

5

2

47.domain:

range:

2

–4^0

y

x

h(x) =^12 x + 2

1 - q, q 2

1 - q, q 2 ;

49.domain:

range:

2

1

0

y

x

G(x) = 2x

1 - q, q 2

1 - q, q 2 ; 51.domain: ;

range:

–4

0

y

x

g(x) = –4

5 - 46

1 - q, q 2

53.domain: ;

range:

xx

yy

00

ff((xx)) = 0= 0

506

1 - q, q 2 55.x-axis 57. (a)$11.25 (b)3 is

the value of the independent variable,

which represents a package weight of 3 lb;

is the value of the dependent vari-

able, representing the cost to mail a 3-lb

package. (c)$18.75; ƒ 152 =18.75

ƒ 132

59. (a)194.53 cm (b)177.29 cm (c)177.41 cm (d)163.65 cm


60. (a) (b)1600; The cost to print 125 t-shirts is
    $1600. (c)75; The cost to print 75 t-shirts is $1000.


61. (a)1.1 (b) 5 (c) (d) 0, 3.5 (e)


62. (a) (b)25 hr; 25 hr (c)2000 gal
    (d) The pool is empty at time 0. (e)
    After 25 hr, there are 3000 gal of water in the pool. 67. 4 69. 4


63. 526

ƒ 102 =0; ƒ 1252 =3000;

3 0, 100 4 ; 3 0, 3000 4

• 1.2 1 2 ƒ 1 x 2 =-1.2x+3.5

ƒ 1752 =1000;

ƒ 1 x 2 = 12 x+ 100

Chapter 3 Review Exercises (pages 202 –204)

1. 
   
   
   
   2. 
      
   
   
   
   


2. 3, 0 ; 4. ; 0, 4


3. 10, 0 ; 0, 4 6. 8, 0 ;


4. 0, 2 8. 9. 10. 11. 2 12. 13.undefined


5. 
   
   
   
   15. 16.undefined 17. 18. 19.positive
       20.negative 21.undefined 22. 0 23.12 ft 24.$1496 per yr
   
   
   
   


6. (a) (b) 26. (a)
   (b) 27. (a) (b)


7. (a) (b) 29. (a)not possible
   (b) 30. (a) (b)


8. (a) (b) 32. (a)
   (b) 33. (a) (b)


9. (a) (b) 35. (a) ;
   $843 (b) ; $723 36. (a) ;
   The revenue from skiing facilities increased by an average of
   $143.75 million each year from 2003 to 2007. (b)$2558 million

y= 47 x+ 159 y=143.75x+1407.75

y=- 25 x + 13 5 x+ 2 y= 26 y= 57 x+ 159

x+y= 2 y= 4 x- 29 4 x-y= 29

y=^75 x+^1657 x- 5 y=- 16 y=-x+ 2

x= 2 y=- 9 x+ 13 9 x+y= 13

y= 3 x+ 7 3 x-y=- 7

y=- 2 y=-^43 x+^2934 x+ 3 y= 29

y=- 31 x- 1 x+ 3 y=- 3 y=- 2

(^23) - (^13) - (^13) - 1
3

• 4
  1


• 2
  7
  A- 5
  9
  2 ,

3

1 2 2 B

0

–2

8

y

x

x – 4y = 8

1 21 0, - 22

0 4 10

4

y

x

2 x + 5y = 20

1 21 2

0 2

4

–4

y

x

28

5

5 x + 7y = 28

A^285 , 0B 1 2

03

–4

y

x

4 x – 3y = 1 2

1 21 0, - 42

xx

yy

00

x x – – y y = 8= 8

(6, –2)(6, –2)

(5, –3)(5, –3)

(2, –6)(2, –6)

(3, –5)

0

(0, 5)

(2, 2)

y

(^103 , 0)

14

( 3 , –2)

x

3 x + 2y = 10

xy

05

0

22

(^143) - 2
10
3
xy
26
53
35
62 -

• 
  


• 
  


•