答案1
\documentclass[a4paper,12pt]{article}
\usepackage{amsmath,amssymb}
\begin{document}
\begin{align*}
\textup{Maximize or Minimize}\quad z &= c_0+c_1x+\dotsb + c_nx_n\\
\text{subject to:}\hspace{43pt} & \\
& \hspace{-5pt}a_{i1}x_1 +a_{i2}x_2+\dotsb +a_{in}x_n \hspace{5pt} \begin{matrix}
\leq\\ \geq \\ =
\end{matrix}\hspace{20pt} i=1, \ldots , m \\
& \hspace{-5pt}x_j\,\biggl\{\begin{matrix}
\geq\\ \gtrless
\end{matrix}\hspace{138pt} j=1, \ldots , n.
\end{align*}
\end{document}
答案2
\documentclass{article}
\usepackage{amsmath,amssymb}
\begin{document}
\[
\begin{array}{cll}
\text{Maximize or Minimize} & z = c_0 + c_1x + \dots + c_nx_n\\
\text{subject to:}\\
& a_{i1}x_1 + a_{i2}x_2 + \dots + a_{in}x_n
\begin{array}{c} \le\\ \ge\\ =\end{array} b_i
& i = 1, \dots, m\\
& x_j\left\{\begin{array}{l} \ge 0\\ \gtrless 0\end{array}\right.
& j=1, \dots, m.
\end{array}
\]
\end{document}