Which of the following options results in a graph that shows exponential growth? (2 points) f(x) = 0.4(3)x
f(x) = 3(0.5)x
f(x) = 0.8(0.9)x
f(x) = 0.9(5)−x

Step-by-step explanation:

The formula for exponential equations is

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

which isn't even exponential!)