Question:
Factorize:
$2 x^{2}-7 x-15$
Solution:
We have:
$2 x^{2}-7 x-15$
We have to split $(-7)$ into two numbers such that their sum is $(-7)$ and their product is $(-30)$, i.e., $2 \times(-15)$.
Clearly, $(-10)+3=-7$ and $(-10) \times 3=-30$
$\therefore 2 x^{2}-7 x-15=2 x^{2}-10 x+3 x-15$
$=2 x(x-5)+3(x-5)$
$=(x-5)(2 x+3)$