使用环境的两个实例aligned
。
\documentclass{article}
\usepackage{mathtools}
\begin{document}
\begin{equation}
\left.
\begin{aligned}
a &= b \\
c &= d \\
e &= f
\end{aligned}
\right\} \quad
\begin{aligned}
g &= h \\
i &= j
\end{aligned}
\end{equation}
\end{document}