Question:
Factorize:
$2 x^{2}+3 x-90$
Solution:
We have:
$2 x^{2}+3 x-90$
We have to split 3 into two numbers such that their sum is 3 and their product is $(-180)$, i.e., $2 \times(-90)$.
Clearly, $-12+15=3$ and $-12 \times 15=-180$
$\therefore 2 x^{2}+3 x-90=2 x^{2}-12 x+15 x-90$
$=2 x(x-6)+15(x-6)$
$=(x-6)(2 x+15)$