Answer
$\dfrac{5x^{2}-125}{x^{2}+2x-15}=\dfrac{5(x-5)}{x-3}$
Work Step by Step
$\dfrac{5x^{2}-125}{x^{2}+2x-15}$
Take out common factor $5$ from the numerator and factor the denominator:
$\dfrac{5x^{2}-125}{x^{2}+2x-15}=\dfrac{5(x^{2}-25)}{(x+5)(x-3)}=...$
Factor $x^{2}-25$ and simplify:
$...=\dfrac{5(x-5)(x+5)}{(x+5)(x-3)}=\dfrac{5(x-5)}{x-3}$
