<imgwidth="14"height="16"v:shapes="_x0000_i1244"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image264.png">个未知量的齐次线性方程组<imgwidth="54"height="20"v:shapes="_x0000_i1245"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image297.png">有非零解的充分必要条件是()
①
方程个数<imgwidth="46"height="16"v:shapes="_x0000_i1246"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image299.png">
②
方程个数<imgwidth="46"height="16"v:shapes="_x0000_i1247"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image301.png">
③
方程个数<imgwidth="46"height="16"v:shapes="_x0000_i1248"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image303.png">
④
<imgwidth="70"height="28"v:shapes="_x0000_i1249"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image305.png">