Answer:
Step-by-step explanation:
The formula for exponential equations is
[tex]y=a(b)^x[/tex] where a is the initial value and b is the growth rate. If b is greater than 1, we have growth; if 0 < b < 1, then we have decay. The only choice that shows a b value greater than 1 is the first one where b = 3. (The last one is also a decay as it can be written as
[tex]f(x)=0.9(\frac{1}{5x})[/tex] which isn't even exponential!)