\begin{equation}x^{2}=16\end{equation}

\begin{equation}7x^{2}-567=0\end{equation}

\begin{equation}4x^{2}=36\end{equation}

\begin{equation}8(x-7)(x-5)=0\end{equation}

\begin{equation}\frac{1}{x+9}=\frac{x^{2}}{x^{2}-81}-(\frac{1}{x-9})\end{equation}

\begin{equation}\frac{1}{7} \times (x+8)(x-8)=0\end{equation}