- Find a nontrivial element of the left null space of $A$.
\begin{equation*}
A=
\begin{bmatrix}
2 & 1 & -3 & 4\\
-1 & -1 & 2 & -1\\
0 & -1 & 1 & 2
\end{bmatrix}
\end{equation*}
- Find the matrices $C$ and $L$ in the extended echelon form of $A$.
\begin{equation*}
A=
\begin{bmatrix}
-9 & 5 & -3 \\
2 & -1 & 1 \\
-5 & 3 & -1
\end{bmatrix}
\end{equation*}
- Why is Theorem FS a great conclusion to Chapter M?