简答题:判断向量组<img src="http://www.weimei168.com/uploads/202208/161267045912331.png" width="20" height="29" />=(1，2，1)<img src="http://www.weimei168.com/uploads/202208/161267047455051.png" width="14" height="25" />，<img src="http://www.weimei168.com/uploads/202208/161267048184251.png" width="24" height="29" />=(2，3，3)<img src="http://www.weimei168.com/uploads/202208/161267047455051.png" width="14" height="25" />，<img src="http://www.weimei168.com/uploads/202208/161267048795571.png" width="22" height="30" />=(3，7，1)<img src="http://www.weimei168.com/uploads/202208/161267047455051.png" width="14" height="25" />是否为R<img src="http://www.weimei168.com/uploads/202208/161267049623951.png" width="12" height="25" />的基．若是，求出向量β=(3，1，4)<img src="http://www.weimei168.com/uploads/202208/161267052012841.png" width="14" height="25" />在这组基下的坐标．