已知xy=-2,x-y=3,求(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y

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已知xy=-2,x-y=3,求(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y

已知xy=-2,x-y=3,求(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y
已知xy=-2,x-y=3,求(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y

已知xy=-2,x-y=3,求(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y
(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y
=(x+y)(x-y)-y^2+(x-y)^2-2y(3x^2-xy)÷2y
=(x+y)(x-y)-y^2+(x-y)^2-(3x^2-xy)
=(x+y)(x-y)+(x-y)^2-y^2-(3x^2-xy)
=[(x+y)+(x-y)](x-y)-y^2-(3x^2-xy)
=2x(x-y)-y^2-(3x^2-xy)
=2x^2-2xy-y^2-3x^2+xy
=-x^2-xy-y^2
=-(x^2+y^2+xy)
=-(x^2-2xy+y^2+3xy)
=-[(x-y)^2+3xy]
=-[3^2+3*(-2)]
=-(9-6)
=-3

(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y
=x²-y²-y²+x²+y²-2xy-3x²+2xy
=-x²-y²+2xy-2xy
=-[(x-y)²+2xy]
=-[9-4】
=-5

x=-1,y=2,代入可得3