Factorise x8−y8
(x4)2−(y4)2
=(x4−y4)(x4+y4) [Using identitya2−b2=(a−b)(a+b)]
={(x2)2−(y2)2}(x4+y4)
={(x2−y2)(x2+y2)}(x4+y4)
=(x−y)(x+y)(x2+y2)}(x4+y4)
Factorie:x8-y8