Question

Разложите на множители:
9а^2-4b^2
25x^2-y^2

Answer 1

$9a^2-4b^2=(3a)^2-(2b)^2=(3a-2b)(3a+2b)$
$25x^2-y^2=(5x)^2-y^2=(5x-y)(5x+y)$