Growth and Decay with Functions

Question

Identify the initial amount a and the decay factor b in the function. Then decide if the function is growth or decay and find F(2).

F(x)=12*(0.75)^x

Answer 1

Initial amount is what F(x) equals when x=0.

So a=12

The decay factor is the rate at which it is decaying, and this can be found by subtracting what is in the parentheses from 1.

So b=1-0.75=0.25 or 25% decay.

The function is decay because the constant which is raised to the power of x is less than one and greater than zero ( 0<0.75<1)

To find F(2), just plug in 2 for x

F(2)=12*(0.75)²

F(2)=27/4