+33661 $${{\mathtt{x}}}^{{\mathtt{2}}}{\mathtt{\,-\,}}{\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{15}} = {\mathtt{0}} \Rightarrow \left\{ \begin{array}{l}{\mathtt{x}} = {\mathtt{1}}{\mathtt{\,-\,}}{\sqrt{{\mathtt{14}}}}{\mathtt{\,\times\,}}{i}\\
{\mathtt{x}} = {\sqrt{{\mathtt{14}}}}{\mathtt{\,\times\,}}{i}{\mathtt{\,\small\textbf+\,}}{\mathtt{1}}\\
\end{array} \right\} \Rightarrow \left\{ \begin{array}{l}{\mathtt{x}} = {\mathtt{1}}{\mathtt{\,-\,}}{\mathtt{3.741\: \!657\: \!386\: \!773\: \!941\: \!4}}{i}\\
{\mathtt{x}} = {\mathtt{1}}{\mathtt{\,\small\textbf+\,}}{\mathtt{3.741\: \!657\: \!386\: \!773\: \!941\: \!4}}{i}\\
\end{array} \right\}$$
.
.+33661 $${{\mathtt{x}}}^{{\mathtt{2}}}{\mathtt{\,-\,}}{\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{15}} = {\mathtt{0}} \Rightarrow \left\{ \begin{array}{l}{\mathtt{x}} = {\mathtt{1}}{\mathtt{\,-\,}}{\sqrt{{\mathtt{14}}}}{\mathtt{\,\times\,}}{i}\\
{\mathtt{x}} = {\sqrt{{\mathtt{14}}}}{\mathtt{\,\times\,}}{i}{\mathtt{\,\small\textbf+\,}}{\mathtt{1}}\\
\end{array} \right\} \Rightarrow \left\{ \begin{array}{l}{\mathtt{x}} = {\mathtt{1}}{\mathtt{\,-\,}}{\mathtt{3.741\: \!657\: \!386\: \!773\: \!941\: \!4}}{i}\\
{\mathtt{x}} = {\mathtt{1}}{\mathtt{\,\small\textbf+\,}}{\mathtt{3.741\: \!657\: \!386\: \!773\: \!941\: \!4}}{i}\\
\end{array} \right\}$$
.
