Rewrite as .

Since both terms are perfect squares, factor using the difference of squares formula, where and .

Rewrite as .

Check the middle term by multiplying and compare this result with the middle term in the original expression.

Simplify.

Factor using the perfect square trinomial rule , where and .

Factor out of .

Cancel the common factors.

Factor out of .

Cancel the common factor.

Rewrite the expression.

Simplify (x^2-36)/(x^2-12x+36)