(x^2 - 2y^4 )
512 + 27a^9 =
(9a^2 + 3ab + b^3)
27a^3 - b^3 =
(94 - 24a^3 + 9a^6)
(x^4 + 2x^2 y^4 + 4y^8)
x^6 - 8y^12 =
(1 - 9x^2 + 81x^4)
(3a - b)
1 + 729x^6 =
(8 + 3a^3 )
(1 + 9x^2 )