$\begin{align}
(E'A')^{\tau} &= ((M^{\tau}M)(M^{-1}AM))^{\tau} = (M^{\tau}AM)^{\tau} \label{oznaka1} \\
&= M^{\tau}A^{\tau}(M^{\tau})^{\tau} = M^{\tau}AM = M^{\tau}M(M^{-1}AM) \notag \\
&= E'A' \label{oznaka2}
\end{align}$