Question 186433
I will do one and you can do the other.

Find the inverse of f(x)= 4x^3-1.

First, let f(x) = y.

y = 4x^3 - 1

Now switch places with x and y.

x = 4y^3 - 1

Next, solve for y.

x + 1 = 4y^3

(x + 1)/4 = y^3

Taking the cube root of each side we get:

cuberoot{(x + 1)/4)} = y

We now replace y with the inverse function notation f^(-1)x.

f^(-1)x = cuberoot{(x + 1)/4)} and it is a function.