填空题:已知<img src="http://www.weimei168.com/uploads/202208/161266935784621.png" width="20" height="29" />=(-1，1，0)<img src="http://www.weimei168.com/uploads/202208/161266936498571.png" width="14" height="25" />，<img src="http://www.weimei168.com/uploads/202208/161266936991701.png" width="24" height="29" />=(2，-1，1)<img src="http://www.weimei168.com/uploads/202208/161266936498571.png" width="14" height="25" />是四元非齐次线性方程组．Ax=b的两个解向量，则 <br /> 对应的齐次线性方程组Ax=0必有一个非零解向量 ξ=_______．