How do you find an exponential growth model

In exponential growth functions, the base of the exponent must be greater than 1,how would the function change if the base of the exponent were 1? how would the fiction change if the base of the exponent were between 0and 1

If 10 men take 18 days to mow 60 acres of grass, how long will 15 men take to mow 80 acres?

Let f(x) = x+3 and g(x) = 1/x the graph of (fog)(x) is shown below what is the range of (fog)(x)?