# How do you simplify (sqrta-4)(sqrta+4)?

$a - 16$

#### Explanation:

$\left(\sqrt{a} - 4\right) \left(\sqrt{a} + 4\right)$

Let's do each multiplication then add up the results:

$\sqrt{a} \sqrt{a} = a$
$\sqrt{a} \left(4\right) = 4 \sqrt{a}$
$\left(- 4\right) \sqrt{a} = - 4 \sqrt{a}$
$\left(- 4\right) \left(4\right) = - 16$

$a + 4 \sqrt{a} - 4 \sqrt{a} - 16 = a - 16$