答案1
您可以使用array
环境:
\[
u_i(a_1, x_2, x_3) - u_i(-a_1, x_2, x_3) = 2a_1\varepsilon_{i1}^0
\qquad
\begin{array}{c}
-a_2 \leq x_2 \leq a_2 \\
-a_3 \leq x_3 \leq a_3
\end{array}
\]
答案2
看看这个 MWE 是否能满足你的要求:
\documentclass{article}
\usepackage{mathtools}
\begin{document}
\begin{align*}
u_i(a_1,x_2,x_3) - u_i(-a_1,x_2,x_3) = 2a_1\varepsilon_{i1}^0
&\quad \begin{aligned}
-a_2\leq x_2 & \leq a_2\\
-a_2\leq x_2 & \leq a_2
\end{aligned} \\
u_i(a_1,x_2,x_3) - u_i(-a_1,x_2,x_3) = 2a_1\varepsilon_{i1}^0
&\quad \begin{aligned}
-a_2\leq x_2 & \leq a_2\\
-a_2\leq x_2 & \leq a_2
\end{aligned}
\end{align*}
\end{document}