The function f is such that f (x) = 4x-1 find f^-1 (x)

Let y=4x-1

The inverse is basically expressing x in terms of y.

y=4x-1 = >

y+1=4x

x = (y+1) / 4

Since the inverse is still a function of x, we only have to interchange x and y

inverse of f (x) = f^-1 (x) = (x+1) / 4