Modeling Decreasing Exponential Functions

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

• ^.08
• ^1.08
• .92
• 8

Classify the model as Exponential GROWTH or DECAY.
A=1200(.85)⁶

• Growth
• Decay

Classify the model as Exponential GROWTH or DECAY.
A=10(1.01)³

• Growth
• Decay

What type of function is y = 7(5/4)^x?

• Exponential Growth
• Exponential Decay
• Linear
• None of the above

Write an equation that models the following situation:
Samantha's hair was known to grow very rapidly. It began at a length of 6 in and grew at a rate of 14% a week.

• y=6(0.14)^x
• y=6(1+14)^x
• y=6(1.14)^x
• y=6(0.86)^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(0.7)^x
• y=30(5000)^x
• y=5000(1.3)^x
• y=5000x^x

A population of fish starts at 8,000 and decreases by 6% per year. What is the population of fish after 10 years?

• 14327
• 4309
• 839
• 7680

Daniel’s Print Shop purchased a new printer for $35,000. Each year it depreciates at a rate of 5%. How much will the printer be worth in 8 years?

• $23,219.72
• $136.72
• $51,710.94
• $16,710.94

• The graph represents an exponential growth situation.
• Eventually, the car will be worth exactly $0.
• The starting value of the car was $12,000.
• The range for the situation is y ≥ 0.

An antibiotic is introduced into a colony of 12,000 bacteria during a laboratory experiment. The colony is decreasing by 14.9% per minute. Which function can be used to model the number of bacteria in the colony after x minutes?

• f(x) = 12000(1 + 14.9)^x
• f(x) = 12000(1 - 14.9)^x
• f(x) = 12000(1 + 0.149)^x
• f(x) = 12000(1 - 0.149)^x