<?xml version="1.0" encoding="UTF-8"?>
<quiz>
  <question type="description">
    <name>
      <text>8.1.1.2 Key point 1</text>
    </name>
    <questiontext format="html">
      <text><![CDATA[<div class="HELM_keypoint">
    <h4>Key point<br></h4>
    <p></p>
    <p>The unique solution to the equations:</p>
    <p>\(\qquad ax+by=e\)</p>
    <p>\(\qquad cx+dy=f\)</p>
    <p>is given by:</p>
    <p>\(\qquad x=\dfrac{\Delta_x}{\Delta},\ \ y=\dfrac{\Delta_y}{\Delta}\)</p>
    <p>in which</p>
    <p>\(\qquad\Delta=\left|\begin{array}{cc}a&amp;b\\ c&amp;d\end{array}\right|,\ \&nbsp;\Delta_x=\left|\begin{array}{cc}e&amp;b\\ f&amp;d\end{array}\right|,\ \ \Delta_y=\left|\begin{array}{cc}a&amp;e\\ c&amp;f\end{array}\right|.\)</p>
    <p>If \(\Delta=0\) this method of solution cannot be used.</p><br>
    <p></p>
</div>]]></text>
    </questiontext>
    <generalfeedback format="html">
      <text/>
    </generalfeedback>
    <defaultgrade>0</defaultgrade>
    <penalty>0</penalty>
    <hidden>0</hidden>
    <idnumber/>
  </question>
</quiz>
