Factorise (a+b)3−(a−b)3
Expanding:
(a+b)3−(a−b)3 =(2b)((a+b)2+(a−b)2+(a+b)(a−b))
=(2b)(3a2−b2)
=(2b)(√3a+b)(√3a−b)
Factorise
(a+b)3+(a-b)3+6a(a2-b2)