\begin{equation}81x^{2}=4\end{equation}

\begin{equation}36x^{2}+12x+1=0\end{equation}

\begin{equation}x^{2}+16=0\end{equation}

\begin{equation}x^{2}+16x+64=0\end{equation}

\begin{equation}x^{2}+18x+162=0\end{equation}

\begin{equation}x^{2}+11x+24=0\end{equation}

\begin{equation}21x^{2}+10x+1=0\end{equation}

\begin{equation}90x^{2}+57x+9=0\end{equation}

\begin{equation}x^{2}+8x+8=0\end{equation}

\begin{equation}4x^{2}+4x-1=0\end{equation}

\begin{equation}49x^{2}+84x+26=0\end{equation}

\begin{equation}36x^{2}+12x+7=0\end{equation}

\begin{equation}64x^{2}+48x+14=0\end{equation}