当(x+1)²+(y+1)²=0时,求3(2x²-xy-y²)-2(x²-2xy-3y²)的值
问题描述:
当(x+1)²+(y+1)²=0时,求3(2x²-xy-y²)-2(x²-2xy-3y²)的值
答
x=-1,y=-1;所求式子等于8
当(x+1)²+(y+1)²=0时,求3(2x²-xy-y²)-2(x²-2xy-3y²)的值
x=-1,y=-1;所求式子等于8