Factor out of .

Factor out of .

Factor out of .

Factor out of .

Factor out of .

Rewrite as .

Let . Substitute for all occurrences of .

Consider the form . Find a pair of integers whose product is and whose sum is . In this case, whose product is and whose sum is .

Write the factored form using these integers.

Replace all occurrences of with .

Remove unnecessary parentheses.

Factor x^3y^2+x^2y-90x