# How do you use the special product of a sum and difference to multiply (3x^2+2)(3x^2-2)?

Dec 11, 2014

Remeber

$\left(a + b\right) \left(a - b\right) = {a}^{2} - {b}^{2}$

By setting $\left\{\begin{matrix}a = 3 {x}^{2} \\ b = 2\end{matrix}\right.$, we have

$\left(3 {x}^{2} + 2\right) \left(3 {x}^{2} - 2\right) = {\left(3 {x}^{2}\right)}^{2} - {\left(2\right)}^{2} = 9 {x}^{4} - 4$

I hope that this was helpful.