Question

докажите тождество: 2ab-(a+b)²+2a²=(a-b)(a+b)

Answer 1

$2ab-(a+b)^2+2a^2=2ab-(a^2+2ab+b^2)+2a^2=\\=2ab-a^2-2ab-b^2+2a^2=a^2-b^2=(a-b)(a+b)$

Answer 2

я не успела