\begin{exercise}{E1}{Linear systems, vector equations, and augmented matrices}{0004}
\begin{exerciseStatement}
Consider the system of equations
\[\begin{matrix}
-3 \, x & - & y & + & 7 \, z & = & 1 \\
& & y & - & 5 \, z & = & 6 \\
-x & & & + & 3 \, z & = & 0 \\
-2 \, x & - & y & + & 7 \, z & = & -2 \\
\end{matrix}\]
\begin{enumerate}[(a)]
\item Write an augmented matrix corresponding to this system.
\item Write a vector equation corresponding to this system.
\end{enumerate}
\end{exerciseStatement}
\begin{exerciseAnswer}
\begin{enumerate}[(a)]
\item \[ \left[\begin{array}{ccc|c}
-3 & -1 & 7 & 1 \\
0 & 1 & -5 & 6 \\
-1 & 0 & 3 & 0 \\
-2 & -1 & 7 & -2
\end{array}\right] \]
\item \[ x_{1} \left[\begin{array}{c}
-3 \\
0 \\
-1 \\
-2
\end{array}\right] + x_{2} \left[\begin{array}{c}
-1 \\
1 \\
0 \\
-1
\end{array}\right] + x_{3} \left[\begin{array}{c}
7 \\
-5 \\
3 \\
7
\end{array}\right] = \left[\begin{array}{c}
1 \\
6 \\
0 \\
-2
\end{array}\right] \]
\end{enumerate}
\end{exerciseAnswer}
\end{exercise}