已知实数x,y,z满足x-y=8,xy+z2=-16,则x+y+z=_.
问题描述:
已知实数x,y,z满足x-y=8,xy+z2=-16,则x+y+z=______.
答
根据题意,得x-y=8,①xy+z2=-16,②由①得y=x-8,③由②得z2=-16-xy,④把③代入④,得 &nbs...
已知实数x,y,z满足x-y=8,xy+z2=-16,则x+y+z=______.
根据题意,得x-y=8,①xy+z2=-16,②由①得y=x-8,③由②得z2=-16-xy,④把③代入④,得 &nbs...