\documentclass[a4paper,11pt]{article}
\usepackage[polish]{babel}
\usepackage[utf8]{inputenc} 
\usepackage[T1]{fontenc}
\usepackage{fourier}



\begin{document}

\begin{equation}
\label{eq:postac:bazowa4}
\left[ 
\begin{array}{ccc}
E & M & c_1\\
\multicolumn{2}{c}{0} & c_2
\end{array}
\right]
\end{equation}

\end{document}