Question

Factorize:

$a^2+2ab+b^2-9c^2$

Answer 1

$a^2+2ab+b^2-9c^2$

$=(a+b{)}^2-(3c{)}^2$

$=(a+b-3c)(a+b+3c)$, [Since, $a^2-b^2=(a+b)(a-b)$]