Rewrite as .

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

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.

Cancel the common factor of .

Factor out of .

Cancel the common factor.

Rewrite the expression.

Multiply and .

Cancel the common factor of .

Cancel the common factor.

Rewrite the expression.

Simplify (x^2-81)/(x^2-3x-54)*(x+6)/x