如果实数x、y、z满足关系式2x+3y-z=0和5x-2y-2x=0,求2x+y-z\x+y-z的值在线等！快！

如果实数x、y、z满足关系式2x+3y-z=0和5x-2y-2x=0,求2x+y-z\x+y-z的值在线等！快！
如果实数x、y、z满足关系式2x+3y-z=0和5x-2y-2x=0,求2x+y-z\x+y-z的值
在线等！快！

如果实数x、y、z满足关系式2x+3y-z=0和5x-2y-2x=0,求2x+y-z\x+y-z的值在线等！快！
整理2x+3y-z=0,得,
2x+3y=z,①
整理5x-2y-2z=0,得,
5x-2y=2z,②
2*①+3*②,得,
x=6z/19,
y=(-4/19)z,代入,得
所以（2x+y-z）\（x+y-z）
=（12z/19-4z/19-z）/(6z/19-4z/19-z)
=(-11/19)/(-17/19)
=11/17