%% %% Der Mathematiksatz mit LaTeX, 1. Auflage 2009 %% %% Example 9-17-8 on page 201. %% %% Copyright (C) 2009 Herbert Voss %% %% 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[]{ttctminimal} \pagestyle{empty} \setcounter{page}{6} \setlength\textwidth{355.65944pt} \AtBeginDocument{\setlength\parindent{0pt}} \setcounter{equation}{25} \renewcommand\theequation{9.\arabic{equation}} \StartShownPreambleCommands \usepackage{mathtools} \StopShownPreambleCommands \begin{document} \begin{gather} \begin{lgathered} i_{11}+i_{21}=0.25\\ i_{21}=\frac{1}{3}i_{11}\\ i_{31}=0.33i_{22}+i_{11}-0.1i_{21} \end{lgathered}\\[5pt] \begin{rgathered} i_{11}+i_{21}=0.25\\ i_{21}=\frac{1}{3}i_{11}\\ i_{31}=0.33i_{22}+i_{11}-0.1i_{21} \end{rgathered}\\[5pt] \begin{gathered} i_{11}+i_{21}=0.25\\ i_{21}=\frac{1}{3}i_{11}\\ i_{31}=0.33i_{22}+i_{11}-0.1i_{21} \end{gathered} \end{gather} \end{document}