Learn how to solve factor by difference of squares problems step by step online. Factor the expression 9a^2-9. Factor the polynomial 9a^2-9 by it's greatest common factor (GCF): 9. Simplify \sqrt{a^2} using the power of a power property: \left(a^m\right)^n=a^{m\cdot n}. In the expression, m equals 2 and n equals \frac{1}{2}. Calculate the power \sqrt{1}. Simplify \sqrt{a^2} using the power of a power property: \left(a^m\right)^n=a^{m\cdot n}. In the expression, m equals 2 and n equals \frac{1}{2}.

Factor the expression 9a^2-9