Answer
$5(x-3)(x+3)$
Work Step by Step
Factor out $5$ to obtain:
$=5(x^2-9)$
Write 9 as $3^2$ to obtain:
$=5(x^2-3^2)$
The binomial factor above is a difference of two squares.
RECALL:
A difference of two square 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 $b=3$ to obtain:
$=5(x-3)(x+3)$
