ANSWER

EXPLANATION
To find the expression that is equivalent to

we must first expand

Then we rearrange to find the required expression.
So let's get started.

We expand the parenthesis on the right hand side to get,

We expand again to obtain,

Let us group the cubed terms on the right hand side to get,


We make the cubed terms the subject,

We factor to get,

We expand the bracket on the left hand side to get,

We finally simplify to get,