Answer
$$(7+a^{2})(7-a^{2})$$
Work Step by Step
$49-a^{4}$
This is the difference between two squares.
There is a simple formula for this case:
$x^{2}-y^{2}=(x+y)(x-y)$
So, applying this formula,
We need to take the square of both terms.
$\sqrt 49=7$
$\sqrt a^{4}=a^{2}$
So the answer would look like:
$$(7+a^{2})(7-a^{2})$$
(One with a positive sign and one with a negative sign.)
