\documentclass{article}
\usepackage{dhucs}
\usepackage{plain}

\begin{document}

\begin{plain}
¾È³çÇϼ¼¿ä.
$$\left\{
\eqalign{\alpha&=f(z)\cr \beta&=f(z^2)\cr \gamma&=f(z^3)\cr}
\right\}\qquad\left\{
\eqalign{x&=\alpha^2-\beta\cr y&=2\gamma\cr}\right\}.$$
\end{plain}

\end{document}