# How do you factor completely 9x^2 - 16?

May 13, 2016

A very slightly different way of presenting the calculation:

$\text{ } \left(3 x - 4\right) \left(3 x + 4\right)$

#### Explanation:

Write as:$\text{ } {3}^{2} {x}^{2} - {4}^{2}$

Which is the same as:$\text{ } {\left(3 x\right)}^{2} - {4}^{2}$

It is known that standard form of ${a}^{2} - {b}^{2} = \left(a + b\right) \left(a - b\right)$

So we have:$\text{ } \left(3 x - 4\right) \left(3 x + 4\right)$