Exponential Functions

Which of the following is an exponential function?

• y = x²

• f(x) = 3x³

• y = x³

• f(x) = 3^x

What is the starting amount in the problem below?

f(t) = 300(1.05)^t

• 300

• 1.05

• t

• y

Does the graph represent an exponential growth or an exponential decay function?

• Exponential Growth
• Exponential Decay

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

Pick the equation that is exponential decay

• y=2000(0.88)
• y=0.5(1.88)

Change 6.75% to a decimal.

• 67.5
• .675
• 675
• .0675

The compound interest formula is:
A = P(1 + r)^t

What does the A represent?

• The amount of interest earned.
• The amount of time that has passed.
• The total amount of money after a certain amount of time.
• The amount required to invest.

Bruno was given $2000 when he turned 3 years old.  His parents invested it at a 2% interest rate compounded annually.  No deposits or withdrawls were made.  Which expression can be used to determine how much money Bruno had in the account when he turned 16? 

• 2000(1+0.02)¹³
• 2000(1-0.02)¹³
• 2000(1+0.02)¹⁶
• 2000(1-0.02)¹⁶

Principal: $5000
Interest Rate: 3.75%
Time: 25 years
Compounded Monthly
State the future account balance.

• $12712.31
• $12,749.30
• $12,657.59
• $12550.84

• y¹⁵
• y⁵
• y²
• 2y⁵