%%
%% 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}