Given f (x) = the quantity of 4x plus 1, divided by 3

solve for f-1 (3).

First we need to find inverse function of f (x) which is written in a form of (f (x)) ^ (-1)

That means that we are actually looking for function f (y) and we need to solve this equation for "y"

y = (4x + 1) / 3

3y = 4x + 1

4x = 3y - 1

x = (3y - 1) / 4

f (y) = (3y - 1) / 4

Now we simply put the value of 3 instead of y and find the answer:

f (y=3) = (3*3-1) / 4 = 2

Answer is 2