%%
%% The LaTeX Companion, 3ed
%%
%% Example 11-2-5 on page II-134 in "A single equation on several lines: no alignment".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3examargin}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{231.0pt}

  % Shorten the vertical size of the example ...
  \AtBeginDocument{%
    \setlength\abovedisplayskip{.3\abovedisplayskip}%
    \setlength\belowdisplayskip{.3\belowdisplayskip}%
  }

%StartShownPreambleCommands
\usepackage{amsmath}
%StopShownPreambleCommands

\begin{document}
\begin{multline}
 \text{First line of a multline}    \\
 \text{Centered Middle line}        \\
 \shoveright{\text{A right Middle}} \\
 \text{Another centered Middle}     \\
 \text{Yet another centered Middle} \\
 \shoveleft{\text{A left Middle}}   \\
 \text{Last line of the multline}
\end{multline}
\end{document}