The simplified form of $(x + 2y)^3 + (x - 2y)^3 $ is : |
$2x^3 + 24 xy^2 $ $2x^3 - 24 xy^2 $ $x^3 - 8 y^3 $ $x^3 + 8 y^3 $ |
$2x^3 + 24 xy^2 $ |
(x + 2y)3 + (x - 2y)3 a3 + b3 = (a + b)(a2 + b2 - ab) (x + 2y)3 + (x - 2y)3 = (x + 2y + x - 2y)[(x + 2y)2 + (x - 2y)2 - (x + 2y)(x - 2y)] = (x + x)[(x2 + 4y2 + 4xy + x2 + 4y2 - 4xy - x2 + 4y2)] = 2x(x2 + 12y2) = 2x3 + 24 xy2 |