Hệ nào sau đây phụ thuộc tuyến tính: 

\[\left\{ {{u_1} = ( - 2,1, - 1),{u_2} = (1, - 1, - 1),{u_3} = ( - 1,0, - 2)} \right\}\]

\[\left\{ {{u_1} = (1,1,2),{u_2} = (1, - 1, - 1),{u_3} = (2,1,1)} \right\}\]

\[\left\{ {{u_1} = (1,1),{u_2} = ( - 1,1),{u_3} = (2,1,1)} \right\}\]

\[\left\{ {{u_1} = (1,1,0),{u_2} = (0,1,0),{u_3} = (0,0,1)} \right\}\]