%%
%% Der LaTeX-Begleiter, zweite Auflage (September 2005)
%%
%% Beispiel 8-2-17 von Seite 489.
%%
%% Copyright (C) 2005 Frank Mittelbach, Michel Goossens,
%%    Johannes Braams, David Carlisle, and Chris Rowley
%%
%% Uebersetzung: Copyright (C) 2005 Claudia Krysztofiak,
%%    Rebecca Stiels und Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%%
%% See http://www.latex-project.org/lppl.txt for details.
%%

\documentclass{lb2examargin}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{173.4372pt}

\StartShownPreambleCommands
\usepackage{amsmath}
\StopShownPreambleCommands
\begin{document}
\renewcommand\minalignsep{2em}
\begin{align}
  x      &= y      && \text{per Hypothese}  \\
      x' &= y'     && \text{per Definition} \\
  x + x' &= y + y' && \text{per Axiom 1}
\end{align}
\end{document}