4258a39f-a0bd-4c8b-97e0-05b9ee9d3531.html

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  <h2>Lesson Summary</h2>
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    <p>To emphasize that the method we choose for solving a system may depend on the system and that some systems are more conducive to solving by substitution than others, present the following systems to students: </p>
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          <p>System 1</p>
          <p><span class="math math-repaired">\( \begin {cases} 3m + n = 71\\2m-n =30 \end {cases} \)</span></p>
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          <p>System 2</p>
          <p><span class="math math-repaired">\( \begin {cases} 4x + y = 1\\y = -2x+9 \end {cases} \)</span></p>
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          <p>System 3</p>
          <p><span class="math">\( \displaystyle \begin{cases} 5x+4y=15 \\ 5x+11y=22 \end{cases} \)</span></p>
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    <p>Ask students to choose a system and make a case (in writing, if possible) for why they would or would not choose to solve that system by substitution. Consider asking students to use sentence starters such as these:</p>
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      <li>I would choose to solve system <span class="math math-repaired">\( \underline{\hspace{0.5in}} \)</span> by substitution because . . .</li>
      <li>I would <em>not</em> choose to solve system <span class="math math-repaired">\( \underline{\hspace{0.5in}} \)</span> by substitution because . . <br></li>
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    <p>With a little bit of rearrangement, all systems could be solved by substitution without cumbersome computation, but system 2 would be most conducive to solving by substitution.</p>
    <p>Consider collecting students&rsquo; responses or asking them to share their written arguments with a partner. </p>
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