Answer
$-2(2x-1)(2x+1)(x^{2}+2)$
Work Step by Step
We factor:
$4-14x^{2}-8x^{4}$
First we factor out $-2$:
$-2(4x^{4}+7x^{2}-2)$
Next we factor in two parts:
$-2(4x^{2}-1)(x^{2}+2)$
Next we use the fact that $(a-b)(a+b)=a^2-b^2$:
$-2(2x-1)(2x+1)(x^{2}+2)$
