Exponential Functions Mixed Practice

Which of the tables below would represent an exponential function? (choose all that apply)

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• 
• 
• 

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. By what percentage is the colony decaying?

• 87%

• 13%

• 800%

• 8.7%

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.

A collectible car has been going up in price by 10% each year. If the car is already worth $29,000, how much will the car be worth in 5 years?

• $0.29

• $2,900,000,000

• $46,704.79

• $145,000

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

• The number of elephants was 1,015 in 1975.

• The number of elephants increases by 1.5% each year.

• The number of elephants increases by 101.5% each year.

• The number of elephants is multiplied by 1.015 each year.

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

• y=8(15,000)^x

• y=15,000(1 + .08)^x

• y=15,000(1 - .08)^x

• y=15,000(0.08)^x

What is the x-intercept of the exponential function?

• (-5,0)

• (0,0)

• There is not one

• (-10,0)

Write the equation of the graph.

• f(x) = 5^x + 2

• f(x) = 3^x - 2

• f(x) = 3^x + 2

• f(x) = -3^x +2

Which function models this table?

Which equation matches the graph?

• y = 2^x+3

• y = 2^x + 3

• y = 2^x

• y = 2^-x