Sums and Differences of Cubes - Expii

2 is a root of x³-2³, so by the factor theorem, x-2 is a factor of x³-2³. In general, x-y is a factor of x³-y³ = (x-y)(x²+xy+y²), while x+y is a factor of x³+y³ = (x+y)(x²-xy+y²).