Intermediate Algebra (11th edition)

SECTION 3.6 Function Notation and Linear Functions 197

64.The table represents a linear function.

(a)What is?

(b)If what is the value of x?

(c)What is the slope of the line?

(d)What is the y-intercept of the line?

(e)Using your answers from parts (c) and (d), write an equation for ƒ 1 x 2.

ƒ 1 x 2 =2.1,

ƒ 122

Find y if See Section 2.1.

Solve each equation. See Section 2.1.

70. 
    
    
    
    71. 
        
        
        
        72. 2 a
        
        
        
        
    
    
    
    

3 x+ 1

2

• 213 x+ 12 + 5 x=- 20 2 x - 41 x- 32 = 8 b-x=- 4

1.5x+2.5y=5.5

4

3

6 x+ 5 y= 2 x+y= 9

x=-3.

PREVIEW EXERCISES

65.Refer to the graph to answer each of the
questions.

(a)What numbers are possible values

of the independent variable? The

dependent variable?

(b)For how long is the water level

increasing? Decreasing?

(c)How many gallons of water are in

the pool after 90 hr?

(d)Call this function ƒ. What is?

What does it mean?

(e)What is? What does it mean?

66.The graph shows megawatts of electricity

used on a summer day.

(a)Why is this the graph of a function?

(b)What is the domain?

(c)Estimate the number of megawatts

used at 8 A.M.

(d)At what time was the most electricity

used? The least electricity?

(e)Call this function ƒ. What is?

What does it mean?

ƒ 1122

ƒ 1252

ƒ 102

02550 100

1000

2000

3000

f

(^0) t
Hours
Gallons
Gallons of Water in a
Pool at Time t
75
4000
700
Hours
Megawatts
900
1100
1300
1500
1700
1900
2100
2300
2500
01248
Noon
16 20 24
Source: Sacramento Municipal Utility
District.
Electricity Use
x
1 3.9
0 2.4
1 0.9
2 0.6
3 2.1

y=ƒ 1 x 2