Answer
$-3(x-5)(x+5)$
Work Step by Step
Factor out $-3$ to obtain:
$=-3(x^2-25)$
Write $25$ as $5^2$ to obtain:
$=-3(x^2-5^2)$
The binomial is a difference of two squares.
RECALL:
A difference of two squares can 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 $b=5$ to obtain:
$=-3(x-5)(x+5)$
