求6x²y+2xy-3x²y²-7x-5yx-4y²x²-6x²y得值,其中|x+3|+(y-½)²=0
问题描述：
求6x²y+2xy-3x²y²-7x-5yx-4y²x²-6x²y得值,其中|x+3|+(y-½)²=0
答
6x²y+2xy-3x²y²-7x-5yx-4y²x²-6x²y |x+3|+(y+1/2)²=0 x=-3 y=1/2
=-3xy-7x²y²-7x=-x(3y+7xy²+7)=3(3/2-21/4+7)=12