关于数学题（初一下·北师大教材）求xy的值.求xy的值.已知xy=-2,x-y=3,求(x+y)(x-y)-y²+(x-_数学解答

关于数学题（初一下·北师大教材）求xy的值.
求xy的值.
已知xy=-2,x-y=3,求(x+y)(x-y)-y²+(x-y)²-(6x²y-2xy²)÷2y的值.
请在今晚9点前解决,

人气：283 ℃　时间：2020-03-29 09:58:15

解答

(x+y)(x-y)-y²+(x-y)²-(6x²y-2xy²)÷2y
=x^2-y^2-y^2+x^2-2xy+y^2-3x^2+xy
=-x^2-y^2-xy
=-(x-y)^2-3xy
=-3^2-3*(-2)
=-3