(4xy2-2x2y)-( )=x3-2x2y+4xy2+y3．
问题描述：
(4xy2-2x2y)-( )=x3-2x2y+4xy2+y3．
答
-x3-y3
答
(4xy^2-2x^2y)-(-x^3-y^3)=x^3-2x^2y+4xy^2+y^3．