
\documentclass{article}
\usepackage[body={8cm,8cm}]{geometry}
\usepackage{mathtools}
\usepackage{lmodern}
\pagestyle{empty}
\begin{document}
\setlength\arraycolsep{2pt}
\begin{eqnarray}
  a & = & b \\
    & = & cdefghijklmnopqrst
          uvwxyzcdefghijklmno
\end{eqnarray}
\vspace*{-0.5cm}
\begin{align}
  a & = b \\
    & = cdefghijklmnopqrst 
        uvwxyzcdefghijklmno
\end{align}
\end{document}
