Intermediate Algebra (11th edition)

19.Concept Check Match each quadratic function with the description of the parabola that

is its graph.

(a) A.Vertex , opens down

(b) B.Vertex , opens up

(c) C.Vertex , opens down

(d) D.Vertex , opens up

20.Concept Check For , in what quadrant is the vertex if

(a) , (b) , (c) , (d) ,?

Graph each parabola. Plot at least two points as well as the vertex. Give the vertex, axis,

domain, and range in Exercises 27–36. See Examples 1–5.

21. 
    
    
    
    22. 
        
        
        
        23. 
            
        
        
        
        
    
    
    
    


22. 
    
    
    
    25. 
        
        
        
        26. 
            
        
        
        
        
    
    
    
    


23. 
    
    
    
    28. 
        
    
    
    
    


24. 
    
    
    
    30. 
        
    
    
    
    


25. 
    
    
    
    32. 
        
    
    
    
    


26. 
    
    
    
    34. 
        
    
    
    
    

35. 36.

Concept Check In Exercises 37– 42, tell whether a linear or quadratic function would be a

more appropriate model for each set of graphed data. If linear, tell whether the slope should

be positive or negative. If quadratic, tell whether the coefficient a of should be positive or

negative. See Example 6.

37. 
    
    
    
    38. 
        
        
        
        39. 
            
        
        
        
        
    
    
    
    

40. 41. 42.

x^2

ƒ 1 x 2 =

4

3

ƒ 1 x 2 = 21 x- 222 - 3 1 x- 322 - 2

ƒ 1 x 2 =-

2

3

ƒ 1 x 2 =- 1 x+ 222 + 1

1

2

1 x+ 122 + 2

ƒ 1 x 2 = 21 x- 222 - 4 ƒ 1 x 2 = 31 x- 222 + 1

ƒ 1 x 2 = 1 x+ 222 - 1 ƒ 1 x 2 = 1 x- 122 + 2

ƒ 1 x 2 = 1 x- 422 ƒ 1 x 2 = 1 x+ 122

ƒ 1 x 2 =x^2 + 3 ƒ 1 x 2 =-x^2 + 2 ƒ 1 x 2 =-x^2 - 2

ƒ 1 x 2 =- ƒ 1 x 2 =x^2 - 1

1

3

ƒ 1 x 2 =- 2 x^2 x^2

h 70 k 70 h 70 k 60 h 60 k 70 h 60 k 60

ƒ 1 x 2 =a 1 x-h 22 +k

ƒ 1 x 2 =- 1 x- 222 - 4 1 4, - 22

ƒ 1 x 2 =- 1 x- 422 - 2 1 4, - 22

ƒ 1 x 2 = 1 x- 222 - 4 1 2, - 42

ƒ 1 x 2 = 1 x- 422 - 2 1 2, - 42

538 CHAPTER 9 Quadratic Equations, Inequalities, and Functions

Year

70

80

90

0

Hours per Person per Year’05 ’07 ’09

TIME SPENT PLAYING

VIDEO GAMES

Source: Veronis Suhler

Stevenson.

y

x

AVERAGE DAILY VOLUME

OF FIRST-CLASS MAIL

Years Since 2000

500

400

600

800

700

0 x

Pieces (in millions)

12345

Source: General Accounting

Office.

y

x

Years Since 1995

100

120

140

160

180

220

(^0281046)
200
Spending (in millions of dollars)
FOOD ASSISTANCE
SPENDING IN IOWA
Source: Iowa Department of
Human Services.
y
Source: Consumer Electronics
Association.
Years Since 2000
1000
2000
3000
4000
6000
(^0145623)
5000
Sales (in millions of dollars)
PLASMA TV SALES
IN U.S.
y
x
Year
15
20
25
30
35
40
0 ’94’98’02’06
Percent
HIGH SCHOOL STUDENTS
WHO SMOKE
y
x
Source: http://www.cdc.gov
Year
SOCIAL SECURITY
ASSETS
Billions of Dollars
2010 ’20 ’30
Projected
Source: Social Security
Administration.
0
1000
2000
3000
4000
y
x