64x^6-y^6=(8x^3)^2 - (y^3)^2=(8x^3-y^3)(8x^3+y^3)=(2x-y)(4x^2+4xy +y^2) . (2x+y)(4x^2-4xy +y^2)=(2x-y)(2x+y)^2 . (2x+y)(2x-y)^2
