Question

(a+b)^2+(a-b)^2=2(a^2+b^2)

Answer 1

(а+b)²+(a-b)²=2(a²+b²)
(a+b)²+(a-b)²=a²+2ab+b²+a²-2ab+b²=2a²+2b²=2(a²+b²)