Interpret Exponential Functions

The value of a car is $15,000 and depreciates at a rate of 8% per year. What is the decay factor?

• ^.08

• ^1.08

• .92

• 8

Suppose 30 flour beetles are left undisturbed in a warehouse bin. The beetle population doubles each week. What function represents this situation?

y = -2(5)^x
Evaluate when x = 3

• -250

• 250

• -1000

• 1000

The amount of ants in a colony, f, that is decaying can be modeled by                         f(x) = 800(.87)^x, where x is the number of days since the decay started. Suppose           f(20) = 49. Which of the following is true?

• After 20 days, there are 49 ants in the colony.

• After 49 days there are 20 ants in the colony.

• The amount of ants times 20 is 49.

• After 20 days the amount of ants remaining decreases by 49.

Write an equation that models the following situation:
Samantha's hair was known to grow very rapidly. It began at a length of 6 in and grew at a rate of 14% a week.

• y=6(0.14)^x

• y=6(1+14)^x

• y=6(1.14)^x

• y=6(0.86)^x

Is the pictured graph growth, decay, or linear or none?  

• Growth

• Decay

• Linear

• None

Is the pictured graph growth, decay, or linear or none?  

• Growth

• Decay

• Linear

• None

What type of function is f(x)=2(1/7)^x ?

• Exponential Growth

• Linear

• Exponential Decay

• None of the Abovee

What type of function is y = 7(5/4)^x?

• Exponential Growth

• Exponential Decay

• Linear

• None of the above

Identify the y-intercept (initial value) in the function f(x)=13(.27)^x

• (.27)^x
• .27
• 13
• 3.51