Exponential Decay Functions

Chelsea is graphing the function f(x) = 20()x. She begins by plotting the initial value. Which graph represents her first step?

c
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-08c.png

Terrence buys a new car for $20,000. The value of the car depreciates by 15% each year. If f(x) represents the value of the car after x years, which function represents the car's value?

a
f(x) = 20,000(0.85)x

Ginny is studying a population of frogs. She determines that the population is decreasing at an average rate of 3% per year. When she began her study, the frog population was estimated at 1,200. Which function represents the frog population after x years?

c
f(x) = 1,200(0.97)x

The table represents an exponential function.
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-29.png
What is the multiplicative rate of change of the function?

3/4

Which is the graph of f(x) = 3(2/3)^x?

d
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-31d.PNG

The table represents an exponential function.
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-27.png
What is the multiplicative rate of change of the function?

a
1/5

Which is the graph of f(x) = 100(0.7)x?

a
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-10a.png

The table represents an exponential function.
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-28.png
What is the multiplicative rate of change of the function?

c
0.5

Which is an exponential decay function?

c
f(x) = 3/2(8/7)-x

Which are true of the function f(x) = 49(1/7)x? Check all that apply.

- The domain is the set of all real numbers.
- The range is y > 0.
- As x increases by 1, each y-value is one-seventh of the previous y-value.

Two exponential functions are shown in the table.
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-24.png
Which conclusion about f(x) and g(x) can be drawn from the table?

The functions f(x) and g(x) are reflections over the y-axis.

A population of bacteria is treated with an antibiotic. It is estimated that 5,000 live bacteria existed in the sample before treatment. After each day of treatment, 40% of the sample remains alive. Which best describes the graph of the function that repr

a
f(x) = 5000(0.4)x, with a horizontal asymptote of y = 0

Which table shows exponential decay?

a
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-04a.png

Hal is asked to write an exponential function to represent the value of a $10,000 investment decreasing at 2% annually. What multiplicative rate of change should Hal use in his function?

0.98

The curve through the ordered pairs (0, 10), (1, 5), and (2, 2.5) can be represented by the function f(x) = 10(0.5)x. What is the multiplicative rate of change of the function?

0.5

Which graph represents exponential decay?

c
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-01c.png

The graph of f(x) = 2x is shown on the grid.
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-21.png
The graph of g(x) = (1/2)x is the graph of f(x) = 2x reflected over the y-axis. Which graph represents

b
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-21b.png

Which is the graph of f(x) = 4(1/2)^x?

b
https://media.education2020.com/evresources/3109/3109-07/3109-07-02/3109-07-02-assessment/3109-07-02-30b.PNG