Solution RREF.C32 Robert Beezer
Following the algorithm of Theorem REMEF, and working to create pivot columns from left to right, we have \begin{align*} \begin{bmatrix} 1 & 1 & 1 \\ -4 & -3 & -2 \\ 3 & 2 & 1 \end{bmatrix} \xrightarrow{\rowopadd{4}{1}{2}} & \begin{bmatrix} 1 & 1 & 1 \\ 0 & 1 & 2 \\ 3 & 2 & 1 \end{bmatrix} \xrightarrow{\rowopadd{-3}{1}{3}} \begin{bmatrix} \leading{1} & 1 & 1 \\ 0 & 1 & 2 \\ 0 & -1 & -2 \end{bmatrix}\\ \xrightarrow{\rowopadd{-1}{2}{1}} & \begin{bmatrix} \leading{1} & 0 & -1 \\ 0 & 1 & 2 \\ 0 & -1 & -2 \end{bmatrix} \xrightarrow{\rowopadd{1}{2}{3}} \begin{bmatrix} \leading{1} & 0 & -1 \\ 0 & \leading{1} & 2 \\ 0 & 0 & 0 \end{bmatrix} \end{align*}