Exponential Graph to Writing Equation

Write an exponential function to model the situation. The value of a car is $18000 and is depreciating at a rate of 12% per year.

• V(t) = .88(18000)^t

• V(t) = .12(18000)^t

• V(t) = 18000(.88)^t

• V(t) = 18000(.12)^t

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

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

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

What is a, the starting term, for the function: f(x) = 300(1.16)^x?

• 300

• 1.16

• .16

• x

Which of the following functions shows an initial amount of $15 and an increase of 35% each year?

• y = 15(35)^x

• y = 15(1 +.35)^x

• y = 15(1- .35)^x

• y = 35(1.15)^x

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

• y=5000(1 - .30)^x

• y=30(1- 5000)^x

• y=5000(1 + .30)^x

• y=5000x^x

Identify the y-intercept (initial value) in the function f(x)=13(.27)^x

• (.27)^x
• .27
• 13
• 3.51

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

• Exponential Growth

• Exponential Decay

• Linear

• None