mtd><mrow></mrow></mtd><mtd><mrow><mo>=</mo></mrow></mtd><mtd><mrow><mn>5</mn><mo>+</mo><mi>x</mi></mrow></mtd></mtr></mtable></mrow><annotation encoding="application/x-tex">\begin{matrix}
 f &amp; = &amp; 2 + x + 3 \\
 &amp; = &amp; 5 + x 
\end{matrix}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="strut" style="height:1.45em;"></span><span class="strut bottom" style="height:2.4000000000000004em;vertical-align:-0.9500000000000004em;"></span><span class="base 