Question

Помогите решить: (a+2b)(a-2b)-(a-b)^2=

Answer 1

a²-4b²-a²+2ab-b²=2ab-5b²

Answer 2

= a^2 - 4b^2 -(a^2 -2ab+b^2)=
= a^2 -4b^2 -a^2 +2ab +b^2=
=2ab - 3b^2=
= b(2a-3b)