6b13119a-e671-4b8d-9765-90b76dfa5867.html

<h3>Cool Down (5 minutes)</h3>
<h4>Student Activity</h4>
<p>The function \(f\) is given by \(f(x)=(x-2)(x+4)\).&nbsp;</p>
<p>Without using graphing technology, answer questions 1&ndash;4.</p>
<ol class="os-raise-noindent">
  <li>What are the \(x\)-intercepts of the graph representing \(f\)?<br>
    <br>
    <strong>Answer:&nbsp;</strong>\(x\)-intercepts for function \(f\): \((2,0)\) and \((-4,0)\)
  </li>
</ol>
<ol class="os-raise-noindent" start="2">
  <li>What is the \(x\)-coordinate of the vertex of the graph?<br>
    <br>
    <strong>Answer:</strong> -1
  </li>
</ol>
<ol class="os-raise-noindent" start="3">
  <li>What is the \(y\)-coordinate of the vertex of the graph?<br>
    <br>
    <strong>Answer:</strong> -9
  </li>
</ol>
<ol class="os-raise-noindent" start="4">
  <li>What is the \(y\)-intercept?<br>
    <br>
    <strong>Answer:</strong>&nbsp;The \(y\)-intercept is \((0,-8)\), because \((0-2)(0+4)=(-2)(4)=-8\).
  </li>
</ol>
<ol class="os-raise-noindent" start="5">
  <li>Use the graphing tool or technology outside the course. Sketch a graph that represents \(f\).&nbsp;</li>
</ol>
<p>(Students were provided access to Desmos.)</p>
<p><strong>Answer:&nbsp;</strong>The graph opens upward with vertex at \((-1,-9)\) and \(x\)-intercepts at \((2,0)\) and \((-4, 0)\).</p>
<p><img alt="Graph on coordinate plane." height="267" src="https://k12.openstax.org/contents/raise/resources/881615b7474f3ba14c771ce12346fe82e703bc6d" width="262"></p>
<h4>Response to Student Thinking</h4>
<h5>Points to Emphasize</h5>
<p>If students struggle to identify the \(x\)- and \(y\)-intercepts, use the Card Sort in Lesson 7.12 to highlight key ideas based on student work in the cool down.</p>