Answer
$(x+3)(x-5)(x+5)$
Work Step by Step
Regroup to obtain:
$=(x^3+3x^2) + (-25x-75)$
Factor out $x^2$ in the first group and $-25$ in the second to obtain:
$=x^2(x+3) + (-25)(x+3)
\\=x^2(x+3) - 25(x+3)$
Factor out the GCF of $x+3$ to obtain:
$=(x+3)(x^2-25)
\\=(x+3)(x^2-5^2)$
Factor the difference of two squares using the formula $a^2-b^2=(a-b)(a+b)$ to obtain:
$=(x+3)(x-5)(x+5)$
