\begin{exercise}{E1}{Linear systems, vector equations, and augmented matrices}{0006}
\begin{exerciseStatement}
Consider the system of equations
\[\begin{matrix}
x_{1} & & & - & x_{3} & = & 3 \\
5 \, x_{1} & + & x_{2} & & & = & 8 \\
-x_{1} & - & x_{2} & - & 3 \, x_{3} & = & 3 \\
-2 \, x_{1} & - & x_{2} & + & x_{3} & = & -3 \\
\end{matrix}\]
\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 \[ \left[\begin{array}{ccc|c}
1 & 0 & -1 & 3 \\
5 & 1 & 0 & 8 \\
-1 & -1 & -3 & 3 \\
-2 & -1 & 1 & -3
\end{array}\right] \]
\item \[ x_{1} \left[\begin{array}{c}
1 \\
5 \\
-1 \\
-2
\end{array}\right] + x_{2} \left[\begin{array}{c}
0 \\
1 \\
-1 \\
-1
\end{array}\right] + x_{3} \left[\begin{array}{c}
-1 \\
0 \\
-3 \\
1
\end{array}\right] = \left[\begin{array}{c}
3 \\
8 \\
3 \\
-3
\end{array}\right] \]
\end{enumerate}
\end{exerciseAnswer}
\end{exercise}