Exponential Equations Growth and Decay Word Problems

What is the a-value (or y-intercept) for the function: f(x) = 800(0.85)^x?

• 800

• 0.85

• 0.15

• x

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

• y = 8(15,000)^x

• y = 15,000(1.08)^x

• y = 15,000(0.92)^x

• y = 15,000(0.08)^x

The equation f(x) = 300(1.06)^x is being used to calculate the amount of money in a savings account.  What does the 1.06 represent?

• 6% growth

• 6% decay

• 1.06% growth

• .06% decay

Determine if the equation y = 15(1.35)^x represents exponential growth or decay and justify. Hint: Think about the growth and decay equations.

• Growth, because the scale factor is greater than 1

• Growth, because the scale factor is less than 1

• Decay, because the scale factor is greater than 1

• Decay, because the scale factor is less than 1

Bridge city has a population of 15000 people. Its population is decreasing at a rate of 1.5% each year. Which equation represents the population?

Bridge city has a population of 15000 people. Its population is decreasing at a rate of 1.5% each year. Is the function a growth or decay?

• growth

• decay

Joyville has a population of 20750 people. Its population is increasing at a rate of 2.7% each year. Is this function a growth or decay?

• growth

• decay

Joyville has a population of 20750 people. Its population is increasing at a rate of 2.7% each year. What function best fits this scenario?

Hannonville has a zombie population of 6075. Its population is decreasing at a rate of 0.5% each month because people are fighting back. Is this a growth or decay?

• Growth

• Decay

Hannonville has a zombie population of 6075. Its population is decreasing at a rate of 0.5% each month because people are fighting back. What is the equation that represents this function?