# How do you factor the expression x^2 - 49?

Dec 3, 2015

Apply the difference of squares formula to find
${x}^{2} - 49 = \left(x + 7\right) \left(x - 7\right)$

#### Explanation:

The difference of squares formula states that
${a}^{2} - {b}^{2} = \left(a + b\right) \left(a - b\right)$
(multiply out the right hand side to verify this)

Applying this, we have
${x}^{2} - 49 = {x}^{2} - {7}^{2} = \left(x + 7\right) \left(x - 7\right)$