(3x二次方y-2xy二次方)-(xy二次方-2x二次方y)-(3x二次方y二次方+2x二次方y)-(-3x二次方y二次方-2xy二次方),其中x=-1,y=2

答：
x=-1,y=2
(3x²y-2xy²)-(xy²-2x²y)-(3x²y²+2x²y)-(-3x²y²-2xy²)
=3x²y-2xy²-xy²+2x²y-3x²y²-2x²y+3x²y²+2xy²
=3x²y-xy²
=xy(3x-y)
=(-1)*2*(-3-2)
=-2*(-5)
=10