TeX Quellcode:

\begin{array}{rclcl} \dfrac{1}{2}x^2+12x &=& -72 & \vert & \cdot 2 \cr x^2+24x &=& -144 & \vert & +144 \cr x^2+24x+144 &=& 0 \cr x_{1,2} &=& -\dfrac{24}{2} \pm \sqrt{\left(\dfrac{24}{2}\right)^2-144} \cr x_{1,2} &=& -12 \pm \sqrt{12^2-144} \cr x_{1,2} &=& -12 \pm \sqrt{0} \cr x_{1,2} &=& -12 \cr \cr \mathbb{L} &=& \{-12\}\end{array}