若x3+y3=1000,x2y-xy=-496,则(x3-y3)+(4xy2-2x2y)-2(xy2-y3)= ----

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若x3+y3=1000,x2y-xy=-496,则(x3-y3)+(4xy2-2x2y)-2(xy2-y3)=----若x3+y3=1000,x2y-xy=-496,则(x3-y3)+(4xy2-2x

若x3+y3=1000,x2y-xy=-496,则(x3-y3)+(4xy2-2x2y)-2(xy2-y3)= ----
若x3+y3=1000,x2y-xy=-496,则(x3-y3)+(4xy2-2x2y)-2(xy2-y3)= ----

若x3+y3=1000,x2y-xy=-496,则(x3-y3)+(4xy2-2x2y)-2(xy2-y3)= ----
应该是x3+y3=1000,x2y-xy2=-496
(x3-y3)+(4xy2-2x2y)-2(xy2-y3)
=x^3-y^3+4xy^2-2x^2y-2xy^2+2y^3
= x^3+y^3+2xy^2-2x^2y
=(x^3+y^3)-2(x^2y-x^2y)
=1000+2×496
=1992