%% 
%%  Example 02-09-2 
%%  Copyright (C) 2016 Herbert Voss
%% 
%% ==== 
% Show page(s) 1
%% 
%% 
\documentclass[]{screxa}
\pagestyle{empty}
\setlength\textwidth{328.62788pt}
\setlength\parindent{0pt}
%StartShownPreambleCommands
\usepackage{amsmath}
\makeatletter
\def\tagform@#1{\maketag@@@{\ignorespaces#1\unskip\@@italiccorr}}
\makeatother
%StopShownPreambleCommands
\begin{document}
\begin{subequations}
\begin{align}
y &= d\\   y &= cx+d\\  y &= bx^2+cx+d\\  y &= ax^3+bx^{2}+cx+d
\end{align}
\end{subequations}
\end{document}
