2a^2+2ab ------------------— — 1 a^2+2ab+b^2
(2a²+2ab)/(a²+2ab+b²) - 1 = (2a²+2ab-a²-2ab-b²)/(a+b)²= =(a²-b²)/(a+b)²=(a+b)(a-b)/(a+b)(a+b)=(a-b)/(a+b) a≠-b