Intermediate Algebra (11th edition)

Section 4.1 (pages 219–224)

1.4; 3. 5. 0 7.D; The ordered-pair solution must be in
quadrant IV, since that is where the graphs of the equations intersect.

9. (a)B (b)C (c)A (d)D 11.yes 13.no


10. 
    
    
    
    17. 
        
    
    
    
    


11. 
    
    
    
    21. 
        
        
        
        23. 
            
            
            
            25. 
                
            
            
            
            
        
        
        
        
    
    
    
    


12. 
    
    
    
    29. 
        
        
        
        31. 
            
        
        
        
        
    
    
    
    


13. dependent equations 35. inconsistent
    system 37. 39. 41. 43.


14. 
    
    
    
    47. dependent equations
    
    
    
    


15. 
    
    
    
    51. inconsistent system 53.
    
    
    
    


16. 
    
    
    
    57. 
        
        
        
        59. 
            
        
        
        
        
    
    
    
    

no solution 61.Both are ; infinitely many

solutions 63. 65. 67.

69. 
    
    
    
    71. 
        
        
        
        73. 75.A
        
        
        
        
    
    
    
    


70. (a) (b)


71. (a)$4 (b)300 half-gallons (c)supply: 200 half-gallons;

demand: 400 half-gallons 81. (a)2004 –2008 (b)2005 and 2006
(c)between 2005 and 2006; about $4000 million (d)

(e)Sales of front projection displays were fairly constant. Sales of plasma
flat panel displays increased from 2003 to 2006, but then declined. Sales

of LCD flat panel displays increased over the whole period, fairly slowly
at first, and then very rapidly. 83.2000, 2001, first half of 2002

85. (Values may vary slightly based on the method of

solution used.) 87. 89. 91.

93. 
    
    
    
    95. 
        
        
        
        97. 4 99.
        
        
        
        
    
    
    
    

Section 4.2 (pages 231–233)

1.B 3. 5. 7.

9. 
   
   
   
   11. 
       
       
       
       13. 
           
       
       
       
       
   
   
   
   


10. 
    
    
    
    17. 
        
        
        
        19. 
            
        
        
        
        
    
    
    
    


11. 
    
    
    
    23. 
        
        
        
        25. 
            
        
        
        
        
    
    
    
    


12. 
    
    
    
    29. 
        
        
        
        31. ; inconsistent system
        
        
        
        
    
    
    
    


13. dependent equations 35.


14. dependent equations 39.


15. ; inconsistent system 43. 45.
    47.100 in., 103 in., 120 in. 49.-4, 8, 12

0 51 2, 1, 5, 3 26 51 - 2, 0, 1, 4 26

51 x, y, z 2 | 2 x+y-z= 66 ; 51 0, 0, 0 26

51 x, y, z 2 | x-y+ 4 z= 86 ; 51 3, 0, 2 26

51 - 4, 6, 2 26 51 - 3, 5, - 626 0

51 2, 2, 2 26 EA^83 , 23 , 3BF 51 - 1, 0, 0 26

51 - 12, 18, 0 26 51 0.8, -1.5, 2.3 26 51 4, 5, 3 26

51 1, 0, 3 (^26) EA1, 103 , 52 BF EA- 37 ,^223 , 7BF
51 3, 2, 1 26 51 1, 4, - 326 51 0, 2, - 526
ea- 8 x- 12 y+ 4 z= 20 - 3
1
a
, - 5 bf
ea
c
a
51 2, 4 26 EA^12 , 2BF , 0bf
1 1.4, 2675.4 2
1 2005, 4000 2
–10
–10 10
51 5, 5 26 10
51 x, y 2 | 4 x-y=- 26 EA1, 21 BF 1 3, - 42
51 - 3, 2 26 EA^13 ,^12 BF 51 - 4, 6 26
y=-^23 x+^13
51 0, - 426 EA6, -^56 BF y=-^37 x+^47 ;y=- 73 x+ 143 ;
EA^32 , - 23 BF 0 ; 51 0, 0 26
51 2, - 326 51 x, y 2 | 7 x+ 2 y= 66 ;
51 4, 2 26 1 0, 0 2 51 2, - 426 51 3, - 126
51 x, y 2 | 2 x-y= 06 ; 0 ;
51 1, 3 26 EA-5, -^103 BF 51 2, 6 26
51 1, 2 26 51 2, 3 26 EA^229 ,^223 BF 51 5, 4 26
–2^14
4
0
y
(2, 2)x
51 2, 2 26
–5
–5
1
0
y
x
(–2, –3)
51 - 2, - 326

• 3 0

Section 4.3 (pages 241–246)

1.wins: 95; losses: 67 3.length: 78 ft; width: 36 ft 5.AT&T:

$124.0 billion; Verizon: $97.4 billion 7. and so the

angles measure 40° and 50°. 9.NHL: $288.23; NBA: $291.93

11.Junior Roast Beef: $2.09; Big Montana: $4.39 13. (a)6 oz

(b)15 oz (c)24 oz (d)30 oz 15. 17.6 gal of 25%;

14 gal of 35% 19.pure acid: 6 L; 10% acid: 48 L 21.nuts: 14 kg;

cereal: 16 kg 23.$1000 at 2%; $2000 at 4% 25. (a) mph

(b) mph 27.train: 60 km per hr; plane: 160 km per hr

29.boat: 21 mph; current: 3 mph 31.$0.75-per-lb candy: 5.22 lb;

$1.25-per-lb candy: 3.78 lb 33.general admission: 76; with student

ID: 108 35.8 for a citron; 5 for a wood apple 37.

angle measures: 70°, 30°, 80° 39.first: 20°; second: 70°; third: 90°

41.shortest: 12 cm; middle: 25 cm; longest: 33 cm 43.gold: 23;

silver: 21; bronze: 28 45.$16 tickets: 1170; $23 tickets: 985;

$40 tickets: 130 47.bookstore A: 140; bookstore B: 280;

bookstore C: 380 49.first chemical: 50 kg; second chemical: 400 kg;

third chemical: 300 kg 51.wins: 53; losses: 19; overtime losses: 10

53. (a) 6 (b) 55. (a) (b)

Section 4.4 (pages 252–253)

1. (a) (b) (c)yes; The number of rows is

the same as the number of columns (three). (d)

(e) (f ) 3. 5.

7. 
   
   
   
   9. 
      
      
      
      11. 
          
          
          
          13. 
              
          
          
          
          
      
      
      
      
   
   
   
   


8. 
   
   
   
   17. 
       
       
       
       19. 
           
       
       
       
       
   
   
   
   


9. 
   
   
   
   23. 
       
   
   
   
   


10. 
    
    
    
    27. 
        
        
        
        29. 
            
        
        
        
        
    
    
    
    


11. 
    
    
    
    33. 
        
        
        
        35. 64 37. 625 39.
        
        
        
        
    
    
    
    

Chapter 4 Review Exercises (pages 257–259)

1. (a)1980 and 1985 (b)just less than 500,000


2. 3.D

4.Answers will vary.

(a) (b) (c)

5. 
   
   
   
   6. 
      
      
      
      7. 
         
         
         
         8. 
            
            
            
            9. 
               
            
            
            
            
         
         
         
         
      
      
      
      
   
   
   
   


6. 
   
   
   
   11. 
       
       
       
       12. ;
           dependent equations 13. 0 ; inconsistent system
       
       
       
       
   
   
   
   

51 - 1, 226 51 - 6, 326 51 x, y 2 | 3 x-y=- 66

EA-^89 , - 34 BF^51 0, 4^2651 2, 4^2651 2, 2^2651 0, 1^26

x

y

x 0

y

x^0

y

0

x + 3y = 8

2 x – y = 2

0

y

x

(2, 2)

51 2, 2 26

81

51 - 1, 2, 1 26 51 1, 7, - (^426256)
51 x, y, z 2 | x- 2 y+z= 46 0 51 1, 1 26
51 - 1, 23, 16 26 51 3, 2, - 426
51 x, y 2 | 2 x+y= 46 51 0, 0 26 51 4, 0, 1 26
51 4, 1 26 51 1, 1 26 51 - 1, 4 26 0
C 3 2 4 2
1
0
1
15
5
4
25

• 3
  8

C S

1

0

1

-^32
5
4
-^12

• 3
  8

S

C

1

0

• 2

4

5

3

8

• 3
  1

S

0, 5, - 3 1, -3, 8

8

• 7
  7


• 8
  1
  6

x+y+z=180;

110 +x 2

110 - x 2

$2.29x

x= 40 y=50,

A-10 Answers to Selected Exercises