Exponential Review 3-15

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

• Exponential Growth
• Exponential Decay

What does the y-intercept of the graph represent?

• The amount of grams the material is gaining.
• The amount of grams the material is losing.
• The amount of grams remaining after so many years.
• The initial amount of grams.

Which of the following is an increasing exponential function whose y-intercept is 50?

• y = 50(.05)^x
• y = 50x - 4
• y = (2)^x + 50
• y = 50(1.4)^x

The amount of ants in a colony, f, that is decaying can be modeled by                      f(x) = 800(.87)^x, where x is the number of days since the decay started. By what percentage is the colony decaying?

• 87%
• 13%
• 800%
• 8.7%

The expression 12(1.015)^t models the population of elephants in a wildlife refuge after t years since 1975.
What does the value 1.015 represent?

• The number of elephants was 1,015 in 1975.
• The number of elephants increases by 1.5% each year.
• The number of elephants increases by 101.5% each year.
• The number of elephants is multiplied by 1.015 each year.