First, the composition (fog)(x) is
(fog)(x) = - 3.
In wording form, it is "take x^3; divide by 8; then subtract 3".
The inverse function to (fog)(x) makes the opposite operations in reverse order.
In other words, (fog)^(-1)(x) makes the following:
it adds 3 to the argument; then multiply by 8; then takes the cube root:
(fog)^(-1)(x) = . ANSWER