iv class="marginpar bmw">
        See 14.2: 1-30 for more practice.
    </div>Do these problems (without using L'Hopital's rule).
    <ol>
      <li>Compute $\ds \lim_{x\to 2} x^2-3x+5$ and then
      $\ds\lim_{(x,y)\to (2,1)} 9-x^2-y^2$.</li>

      <li>Compute $\ds\lim_{x\to 3}\frac{x^2-9}{x-3}$ and then
      $\ds\lim_{(x,y)\to (4,4)} \frac{x-y}{x^2-y^2}$.</li>

      <li>Explain why $\ds\lim_{x\to 0}\frac{x}{|x|}$ does not
      exist. [Hint: graph the function.]</li>
    </ol>
  </div>
                