%% 
%%  Example 02-01-14 
%%  Copyright (C) 2016 Herbert Voss
%% 
%% ==== 
% Show page(s) 1
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\documentclass[]{screxa}
\pagestyle{empty}
\setlength\textwidth{134.31393pt}
\setlength\parindent{0pt}
%StartShownPreambleCommands
\usepackage{amsmath}
%StopShownPreambleCommands
\begin{document}
\begin{equation}
\begin{aligned}
  2x+3 &= 7  &     2x+3-3 &=7-3    \\
  2x   &= 4  & \frac{2x}2 &=\frac42\\
  x    &= 2
\end{aligned}
\end{equation}
\end{document}
