This is an example to illustrate my point:

Any help will be greatly appreciated.
Thanks in advance.
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Code: Select all
\documentclass{article}
\usepackage{framed}
\begin{document}
\begin{leftbar}
text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text \begin{equation}
a=b
\end{equation}
text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text
\end{leftbar}
\end{document}
NEW: TikZ book now 40% off at Amazon.com for a short time.