Question

(a-b)²+(-a+b)²+2(a-b)(b-a)

Answer 1

$(a-b)^{2} + (-a+b) ^{2} + 2(a-b)(b-a) =$
$a^{2} -2ab + b^{2} + a^{2} - 2ab + b^{2} - 2a^{2} + 2b^{2} =$
$-4ab + 4b^{2}$

Answer 2

$(a - b)^2 + (-a + b)^2 + 2.(a - b).(b - a) \\ \\ a^2 - 2ab + b^2 + a^2 - 2ab + b^2 + 2. (-a^2 + 2ab - b^2) \\ \\ 2a^2 - 4ab + 2b^2 + (-2a^2 + 4ab - 2b^2) \\ \\ 2a^2 - 2a^2 - 4ab + 4ab -2b^2 - 2b^2 \\ \\ =\ \textgreater \ 0$