若实数x,y,z满足(x-z)²-4(x-y)(y-z)=0,则下列式子一定成立的是( )A.x+y+z=0 B.x+y-2z=0 c.2x-y-z=0d.x-2y+z =0

问题描述:

若实数x,y,z满足(x-z)²-4(x-y)(y-z)=0,则下列式子一定成立的是( )
A.x+y+z=0
B.x+y-2z=0
c.2x-y-z=0
d.x-2y+z =0

(x-z)²-4(x-y)(y-z)=0x²-2xz+z²-4xy+4xz+4y²-4yz=0x²+2xz+z²-4xy+4y²-4yz=0(x+z)²-4(x+z)y+4y²=0(x+z-2y)²=0即x-2y+z=0选 D