#### Answer

$4(x+2)(x-2)$

#### Work Step by Step

Factoring the $GCF=4$, then the given expression, $
4x^2-16
$, is
\begin{array}{l}
4(x^2-4)
.\end{array}Using $a^2-b^2=(a+b)(a-b)$ or the factoring of the difference of 2 squares, then the factored form of the expression, $
4(x^2-4)
$, is
\begin{array}{l}
4(x+2)(x-2)
.\end{array}