a² – b² = (a-b)(a+b)(a+b)² = a² + 2ab + b²(a-b)² = a² – 2ab + b²a² + b² = (a-b)² +2ab(a+b+c)² = a²+b²+c²+2ab+2ac+2bc(a-b-c)² = a²+b²+c²-2ab-2ac+2bca³-b³ = (a-b) (a² + ab + b²)a³+b³ = (a+b) (a² – ab + b²)(a+b)³ = a³+ 3a²b + 3ab² + b³(a-b)³ = a³- 3a²b + 3ab² – b³“n” is a natural number, an – bn = (a-b) (an-1 + an-2b +….bn-2a + bn-1)“n” is a even number, an + bn = (a+b) (an-1 – an-2b +….+ bn-2a – bn-1)“n” is an odd number an + bn = (a-b) (an-1 – an-2b +…. – bn-2a + bn-1)(am)(an) = am+n (ab)m = amn