Answer
$(5-x)(5+x)$
Work Step by Step
RECALL:
A difference of two square can be factored using the formula
$a^2-b^2=(a-b)(a+b)$
The given binomial can be written as:
$=5^2-x^2$
The binomial above is a difference of two squares.
Factor the difference of two squares using the formula above with $a=5$ and $b=x$ to obtain:
$=(5-x)(5+x)$