Exponential Function Exam

The function y = 125(1.13)^x represents Mr. Gantz's recent investments where x is measured in years.  Which is NOT true?

• Mr. Gantz initial invested $125

• Mr. Gantz's money grows by 13% per year

• After 4 years Mr. Gantz will have about $203.81

• Mr. Gantz earns more money in year one than in year 5

Suppose a culture of bacteria begins with 5000 cells and dies by 30% each year. Write an equation that represents this situation.

• y=5000(0.7)^x

• y=30(5000)^x

• y=5000(1.3)^x

• y=5000x^x

What is the initial value of the situation represented by f(x)=0.05(2)^x?

• 0.05

• 2

• 0.1

• 1

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

Which color represents the graph of an exponential decay function?

• Blue

• Red

• 1.6

• 9

• y

• x

How do you think you would write a function that models the growth of $1500 that earns 8% per year?

y = 7(1.2)^x

• Growth, because of 7

• Decay, because of 1.2

• Growth because of 1.2

• Decay because of 7

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

• Exponential Growth

• Exponential Decay

• Linear

• None of the above

Is this exponential growth or decay?

• Growth because a=1

• Growth because there is no a

• Decay because b=0.5

• Neither because a=0