Solution LI.C33 Robert Beezer
A direct application of Theorem BNS will provide the desired set. We require the reduced row-echelon form of $A$. \begin{align*} \begin{bmatrix} 2 & 3 & 3 & 1 & 4 \\ 1 & 1 & -1 & -1 & -3 \\ 3 & 2 & -8 & -1 & 1 \end{bmatrix} &\rref \begin{bmatrix} \leading{1} & 0 & -6 & 0 & 3 \\ 0 & \leading{1} & 5 & 0 & -2 \\ 0 & 0 & 0 & \leading{1} & 4\end{bmatrix} \end{align*} The non-pivot columns have indices $F=\set{3,\,5}$. We build the desired set in two steps, first placing the requisite zeros and ones in locations based on $F$, then placing the negatives of the entries of columns 3 and 5 in the proper locations. This is all specified in Theorem BNS. \begin{align*} S&= \set{ \colvector{ \\ \\ 1\\ \\ 0},\, \colvector{ \\ \\ 0\\ \\ 1} } = \set{ \colvector{ 6\\ -5\\ 1\\ 0\\ 0},\, \colvector{ -3\\ 2\\ 0\\ -4\\ 1} } \end{align*}