TeX Quellcode:

\begin{array}{rcl} x^2-4x+13 &=& 0 \cr &\dots & \cr x_{1,2} &=& 2\pm \sqrt{-9} \cr x_{1,2} &=& 2\pm \sqrt{9\cdot (-1)} \cr x_{1,2} &=& 2\pm 3\sqrt{-1} \cr x_{1,2} &=& 2\pm 3i \end{array}