I have seen Your question many times before:
If f(x) = 5x, what is f–1(x)
Let's get started:
Note that f^(-1)*(x) means inverse function (not 1/f(x))
Let's say:
y = f(x) = 5x
Then that means: f^(-1)*(x) means "find x in terms of y"
So in other terms:
f^(-1) * (x) =y/5 = f(x)/5
Your final answer is: x= y/5
Hope I helped!!!!!!