# How do you factor (b+2)^2 - (b-2)^2?

Dec 17, 2015

Apply the difference of squares formula and simplify to find

${\left(b + 2\right)}^{2} - {\left(b - 2\right)}^{2} = 8 b$

#### Explanation:

The difference of squares formula states that
${a}^{2} - {b}^{2} = \left(a + b\right) \left(a - b\right)$

In this case, we just happen to have binomials as $a$ and $b$. However, the formula still applies.

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

$= \left(2 b\right) \left(4\right)$

$= 8 b$