已知丨x+1丨+(y+2)²+丨z-1丨=0,求(x+y)²-(y+z)²-(z+x)²
问题描述:
已知丨x+1丨+(y+2)²+丨z-1丨=0,求(x+y)²-(y+z)²-(z+x)²
答
丨x+1丨+(y+2)²+丨z-1丨=0,
则
丨x+1丨=0,x=-1
(y+2)²=0,y=-2
丨z-1丨=0,z=1
求(x+y)²-(y+z)²-(z+x)²=9-1-0=8