答案1
这是一个解决方案 [双关语],它可以创建一个solution
不依赖于其他包的环境。
\documentclass{article}
\usepackage{amssymb} % for '\blacksquare' macro
\newenvironment{solution}{%
\setlength\parindent{0pt}\par\medskip\textbf{Solution}\quad}{%
\hfill\tiny$\blacksquare$\par\medskip}
\begin{document}
\noindent
3. If $G$ is a group such that \dots
\begin{solution}
We have for all $a,b\in G$ \dots
\dots
\medskip
But $b\cdot a=a\cdot b$. \dots
\end{solution}
Some text immediately after the \texttt{solution} environment.
\end{document}