0005.ptx

<exercise checkit-seed="0005" checkit-slug="M1" checkit-title="Multiplying matrices">
  <statement>
    <p>Of the following three matrices, only two may be multiplied.
      <me>
          A= \left[\begin{array}{ccc}
0 &amp; -1 &amp; -2 \\
-2 &amp; -5 &amp; 2 \\
1 &amp; 0 &amp; 0 \\
-1 &amp; -4 &amp; -1
\end{array}\right]  \hspace{1em} B= \left[\begin{array}{cc}
-1 &amp; -5 \\
2 &amp; -5 \\
1 &amp; 1
\end{array}\right]  \hspace{1em} C= \left[\begin{array}{cc}
1 &amp; 2 \\
-2 &amp; -3 \\
-3 &amp; -1 \\
5 &amp; 6
\end{array}\right] </me>
      Explain which two can be multiplied and why. Then show how to find their product.</p>
  </statement>
  <answer>
    <me>AB= \left[\begin{array}{cc}
-4 &amp; 3 \\
-6 &amp; 37 \\
-1 &amp; -5 \\
-8 &amp; 24
\end{array}\right] </me>
  </answer>
</exercise>