Answer
False.
The correct statement is:
$x^4-16$ is factored completely as $(x^2+4)(x-2)(x+2)$.
Work Step by Step
The statement is false.
$x^2-4=x^2-2^2$, a difference of two squares.
A difference of two squares can still be factored using the formula:
$a^2-b^2=(a-b)(a+b)$
Factor the difference of two squares using the formula above with $a=x$ and $b=2$ to obtain:
$x^2-2^2=(x-2)(x+2)$
Thus, the completely factored form of $x^4-16$ is:
$=(x^2+4)(x-2)(x+2)$