\begin{equation}x^{2}=25\end{equation}

\begin{equation}4x^{2}-324=0\end{equation}

\begin{equation}4x^{2}=144\end{equation}

\begin{equation}9(x-9)(x-6)=0\end{equation}

\begin{equation}\frac{1}{x+4}=\frac{x^{2}}{x^{2}-16}-(\frac{1}{x-4})\end{equation}

\begin{equation}\frac{1}{7} \times (x+7)(x-7)=0\end{equation}