\begin{exercise}{A2}{Standard matrices}{0002}
\begin{exerciseStatement}
\begin{enumerate}[(a)]
\item Find the standard matrix for the linear transformation \(S:\mathbb{R}^ 4 \to \mathbb{R}^ 2 \) given by \[S\left( \left[\begin{array}{c}
x \\
y \\
z \\
{w}
\end{array}\right] \right) = \left[\begin{array}{c}
-2 \, x + y - 2 \, {w} \\
x - y
\end{array}\right] .\]
\item Let \(T:\mathbb{R}^ 4 \to \mathbb{R}^ 1 \) be the linear transformation given by the standard matrix \[ \left[\begin{array}{cccc}
1 & -1 & -2 & -1
\end{array}\right] .\] Compute \(T\left( \left[\begin{array}{c}
6 \\
-3 \\
5 \\
-7
\end{array}\right] \right)\).
\end{enumerate}
\end{exerciseStatement}
\begin{exerciseAnswer}
\begin{enumerate}[(a)]
\item \[ \left[\begin{array}{cccc}
-2 & 1 & 0 & -2 \\
1 & -1 & 0 & 0
\end{array}\right] \]
\item \[T\left( \left[\begin{array}{c}
6 \\
-3 \\
5 \\
-7
\end{array}\right] \right)= \left[\begin{array}{c}
6
\end{array}\right] \]
\end{enumerate}
\end{exerciseAnswer}
\end{exercise}