\documentclass[a4paper,11pt]{report}
\usepackage[latin1]{inputenc}
\usepackage[italian]{babel}
\usepackage{graphicx}

\newtheorem{prop}{Proposizione}
\newtheorem{defin}{Definizione}
\newtheorem{oss}{Osservazione}
\newtheorem{ese}{Esempio}


\begin{document}

Se eseguiamo il prodotto tra le matrici otteniamo: \vspace{3mm}
$$
\left(
\begin{array}{ccc}
x' & y' & 1
\end{array}
\right) \left(
\begin{tabular}{ccc}
        & \multicolumn{2}{c}{0}\\
\raisebox{1.5ex}[0cm][0cm]{$P^t$}
         &0                    \\
$\gamma$\quad\, $\delta$&1      \\
\end{tabular}
 \right)
 \left(
 \begin{array}{ccc}
a_{11} & a_{12} & a_{13}\\
a_{12} & a_{22} & a_{23}\\
a_{13} & a_{23} & a_{33}
\end{array}
\right) \left(
\begin{tabular}{ccc}
        & \multicolumn{2}{c}{$\gamma$}\\
\raisebox{1.5ex}[0cm][0cm]{$P$}
           &$\delta$     \\
0\quad\, 0 & 1            \\
\end{tabular}
 \right)
 \left(
\begin{array}{c}
x'\\y'\\1
\end{array}
\right)=
$$
\vspace{3mm}
$$
=\left(
\begin{array}{ccc}
x' & y' & 1
\end{array}
\right) \left(
\begin{tabular}{ccc}
        & \multicolumn{2}{c}{0}\\
\raisebox{1.5ex}[0cm][0cm]{$P^t$}
         &0                    \\
$\gamma$\quad\, $\delta$ &1       \\
\end{tabular}
 \right)
 \left(
 \begin{tabular}{ccc}
        & \multicolumn{2}{c}{$a_{13}$}\\
\raisebox{1.5ex}[0cm][0cm]{$A_0$}
         &$a_{23}$                    \\
$a_{13}$\quad$a_{23}$&$a_{33}$
\end{tabular}
\right) \left(
\begin{tabular}{ccc}
        & \multicolumn{2}{c}{$\gamma$}\\
\raisebox{1.5ex}[0cm][0cm]{$P$}
         &$\delta$                    \\
0\quad\,0&1
\end{tabular}
 \right)
 \left(
\begin{array}{c}
x'\\y'\\1
\end{array}
\right)=
$$
\vspace{3mm}
\begin{equation}
\label{pta0p} =\left(
\begin{array}{ccc}
x' & y' & 1
\end{array}
\right) \left(
\begin{tabular}{ccc}
        & \multicolumn{2}{c}{$b_{13}$}\\
\raisebox{1.5ex}[0cm][0cm]{$P^tA_0P$}
         &$b_{23}$                    \\
$b_{13}$\quad\,$b_{23}$ & $b_{33}$   \\
\end{tabular}
 \right)
 \left(
\begin{array}{c}
x'\\y'\\1
\end{array}
\right)=0. \vspace{3mm}
\end{equation}
\vspace{2mm}
\end{document}
