%% 
%%  Example 02-02-15 
%%  Copyright (C) 2016 Herbert Voss
%% 
%% ==== 
% Show page(s) 1
%% 
%% 
\documentclass[]{screxa}
\pagestyle{empty}
\setlength\textwidth{158.31393pt}
\setlength\parindent{0pt}
%StartShownPreambleCommands
\usepackage{amsmath}
%StopShownPreambleCommands
\begin{document}
\begin{align}\begin{split} a = {}&  -b + c \\ &  -d + e \end{split}\end{align}
%
\begin{align}\begin{split} a = {}&{-}b + c \\ &{-}d + e \end{split}\end{align}
\end{document}
