Question

(a+7)^2+(a-3)^2 - 2(a-3)(a+7)

Answer 1

(a+7)^2-2(a-3)*(a+7)+(a-3)^2
(a+7-(a-3))^2
(a+7-a+3)^2
(a+7-a+3)^2
(7+3)^2
10^2=100

Answer 2

Cпасибо огромное)