You want to factor the expression:

9x^3-36x^2+36x

This is done by pulling out the greatest common factor for each of the terms in the expression, and that is, '9x'.

What is left in the brackets, after, is a square of a binomial:

Clicking on each step (except the first) gives additional explanation. Quite often, several transformations will be performed within the same step. Use the explanation navigation buttons to step through all of them: