Exponential Decay Functions: Quiz

What is the multiplicative rate of change for the exponential function f(x) = 2(5/2)^-x?

A. 0.4

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

A. Graph 1

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

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 represents the number of live bacteria after x days of treatment?

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

The table represents an exponential function. What is the multiplicative rate of change of the function?

B. 2/3

he graph of f(x) = 2x is shown on the grid. The graph of g(x) = (1/2)x is the graph of f(x) = 2x reflected over the y-axis. Which graph represents g(x)?

B. Graph 2

Two exponential functions are shown in the table. Which conclusion about f(x) and g(x) can be drawn from the table?

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

Chelsea is graphing the function f(x) = 20(1/4)x. She begins by plotting the initial value. Which graph represents her first step?

C. Graph Three (0, 20)

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

Which is an exponential decay function?

D. f(x)=1/3(-9/2)