%% 
%%  An UIT Edition example
%% 
%%  Example 04-01-5 on page 34.
%% 
%%  Copyright (C) 2010 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.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{375.57637pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\setcounter{equation}{3}
\renewcommand\theequation{4.\arabic{equation}}
\StartShownPreambleCommands

\StopShownPreambleCommands
\begin{document}
\begin{equation}
  x=\left\{ \begin{array}{cl}
  0 & \textrm{if A=\ldots}\\
  1 & \textrm{if B=\ldots}\\
  x & \textrm{This text can be as long as you want it to be,
              but it will not be wrapped\ldots}
\end{array}\right.
\end{equation}
\end{document}