答案1
您可以测量盒子,并使用调整右侧\raisebox
\documentclass[twocolumn]{article}
\usepackage{amsmath}
\begin{document}
\begin{enumerate}
\item
\sbox0{\parbox[t]{.45\linewidth}{%
$\begin{aligned}[t]
x+y+z+a&=b\\
&\rightarrow c\\
&\rightarrow d\\
&\rightarrow e\\
&\rightarrow f
\end{aligned}$}}
\sbox2{\parbox[c]{.45\linewidth}{%
\begin{tabular}[c]{c|cc}
a&b&c\\\hline
1&2&3
\end{tabular}}}
\usebox{0}\hfill
\raisebox{-.5\dp0}{\usebox{2}}
\end{enumerate}
\end{document}