化简求值(x+y)(x-y)-(x-y)²-6x²y/2y+(2xy)²/(-4xy)其中x=-2,y=1/3
问题描述:
化简求值(x+y)(x-y)-(x-y)²-6x²y/2y+(2xy)²/(-4xy)其中x=-2,y=1/3
答
(x+y)(x-y)-(x-y)²-6x²y/2y+(2xy)²/(-4xy)
=x²-y²-x²+2xy-y²-3x²-xy
=-3x²-2y²+xy
当x=-2,y=1/3时
原式=-12-2/9-2/3
=-12又8/9