Exponential Functions Practice 1

The function given is an example of growth or decay?

 $y=2^x$  

• Growth

• Decay

The function given is an example of growth or decay?

 $y=3\cdot\left(\frac{1}{2}\right)^x$  

• Growth

• Decay

Given the exponential function below, what is the starting value?
 $y=2\cdot0.7^x$  

• 2

• 0.7

• x

The expression 12(1.015)^t models the population of elephants in a wildlife refuge after t years since 1975.
Is the population of elephants increasing or decreasing?

• Increasing
• Decreasing

What is a, the starting value, for the function: f(x) = 300(1.16)^x?

• 300

• 1.16

• .16

• x

The expression 12(1.015)^t models the population of elephants in a wildlife refuge after t years since 1975.
What does the value 12 represent?

• The predicted increase in number of elephants in the refuge each year.
• The predicted decrease in number of elephants in the refuge each year.
• The number of years it will take for the elephant population to stop increasing.
• The initial amount of elephants in the park.

What does this graph represent?

• Exponential Decay

• Exponential Growth

What does the graph represent?

• Exponential Decay

• Exponential Growth

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.

Suppose 30 flour beetles are left undisturbed in a warehouse bin. The beetle population doubles each week. The function below gives the population after x weeks. 

 $f\left(x\right)=30\left(2\right)^x$  
How many beetles will there be after 56 days?

• 7,680 beetles

• 256 beetles

• 1,679,616 beetles

• 480 beetles