已知xy=2,x-y=3,求（x+y）（x-y）-y^2-（6x^2y-2xy^2)/2y的值.
问题描述：
已知xy=2,x-y=3,求（x+y）（x-y）-y^2-（6x^2y-2xy^2)/2y的值.
答
已知xy=2，x-y=3,
（x+y)(x-y）-y²-（6x²y-2xy²)/2y
=x²-y²-y²-3x²+xy
=-2(x²+y²-2xy)-3xy
=-2(x-y)²-3xy
=-2*3²-3*2
=-24
答
（x+y）（x-y）-y^2-（6x^2y-2xy^2)/2y
=x^2-y^2-y^2-3x^2+xy
=-2(x^2+Y^2-2xy)-3xy
=-2(x-y)^2-3xy
=-2*3^2-3*2
=-24
答
（x+y）（x-y）-y^2-（6x^2y-2xy^2)/2y
=x^2-y^2-y^2-3x^2+xy
=-2(x^2+Y^2)+xy
=-2(x^2+Y^2-2xy)-4xy+xy
=-2(x-y)^2-3xy
=-2*3^2-3*2
=-24