X^2 -9x = 0. factor and use the zero property to solve

The first step of factoring is to try to factor out a common factor.
The terms x^2 and -9x have the factor x in common.
Factor out x from both terms.

x^2 - 9x = 0

x(x - 9) = 0

Now you have a product of fully factored terms equaling zero, so you can apply the zero product property to solve.

x = 0   or   x - 9 = 0

x = 0   or   x = 9

x = 0 or x = 9