le="text-align:left;">following dollar character '$' is allowed.</td>
    </tr>
   <tr id="#18">
      <td style="text-align:right;">18</td>
      <td style="text-align:center;">&#128522;</td>
      <td style="text-align:left;">$x$ $y$</td>
      <td style="text-align:left;"><p><eq><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>x</mi></mrow><annotation encoding="application/x-tex">x</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="stru