TeX Quellcode:

\begin{array}{rclll} \mathbb{D} &=& \mathbb{R} \cr\cr f'(x) &=& 4x-12 \cr \cr 0 &=& 4x-12 & \vert & -4x \cr -4x &=& -12 & \vert & :(-4) \cr x &=& 3\end{array}