To divide by a fraction, multiply by its reciprocal.

Rewrite as .

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

Factor out of .

Factor out of .

Factor out of .

Factor out of .

Cancel the common factor of .

Factor out of .

Cancel the common factor.

Rewrite the expression.

Cancel the common factor of .

Factor out of .

Factor out of .

Cancel the common factor.

Rewrite the expression.

Combine and .

Cancel the common factor of .

Cancel the common factor.

Rewrite the expression.

The result can be shown in multiple forms.

Exact Form:

Decimal Form:

Mixed Number Form:

Simplify ((a^2-81)/(49a+441))÷((a-9)/63)