<exercise checkit-seed="0002" checkit-slug="A2" checkit-title="Standard matrices">
<statement>
<ol>
<li>Find the standard matrix for the linear transformation <m>S:\mathbb{R}^ 4 \to \mathbb{R}^ 2 </m> given by
<me>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] .</me></li>
<li>Let <m>T:\mathbb{R}^ 4 \to \mathbb{R}^ 1 </m> be the linear transformation given by the standard matrix
<me> \left[\begin{array}{cccc}
1 & -1 & -2 & -1
\end{array}\right] .</me>
Compute <m>T\left( \left[\begin{array}{c}
6 \\
-3 \\
5 \\
-7
\end{array}\right] \right)</m>.
</li>
</ol>
</statement>
<answer>
<ol>
<li>
<me> \left[\begin{array}{cccc}
-2 & 1 & 0 & -2 \\
1 & -1 & 0 & 0
\end{array}\right] </me>
</li>
<li>
<me>T\left( \left[\begin{array}{c}
6 \\
-3 \\
5 \\
-7
\end{array}\right] \right)= \left[\begin{array}{c}
6
\end{array}\right] </me>
</li>
</ol>
</answer>
</exercise>