若x^3+y^3=1000,且x^2y-xy^2=-496,求(x^3-y^3)+(4xy^2-2x^2y)-2(xy^2-y^3)的值

分类: 作业答案 • 2022-08-04 09:13:36

问题描述：

答

(x^3-y^3)+(4xy^2-2x^2y)-2(xy^2-y^3)
=(x^3+y^3)+(xy^2-x^2y)
=1000+2*(-496)
=8

答

(x^3-y^3)+(4xy^2-2x^2y)-2(xy^2-y^3)
=(x^3+y^3)+4xy^2-2x^2y-2xy^2
=(x^3+y^3)+2(xy^2-x^2y)
=1000+2*496
=1992