已知xy=-2,x-y=3,求(x+y)(x-y)-y²+(x-y)²-(6x²y-2xy²_数学解答

已知xy=-2,x-y=3,求(x+y)(x-y)-y²+(x-y)²-(6x²y-2xy²)÷(2y)的值.

人气：428 ℃　时间：2020-04-24 07:50:32

解答

(x+y)(x-y)-y²+(x-y)²-(6x²y-2xy²)÷(2y)
=x²-y²-y²+x²-2xy+y²-3x²+xy
=-x²-y²-xy
=-x²-y²+2xy-3xy
=-(x-y)²-3xy
=-3²+6
=-3