TeX source:
\begin{array}{rclcl} 0 &=& -x^2 +2x +35 &\vert& \cdot(-1) \cr 0 &=& x^2 -2x -35 &\vert& \text{p-q-Formel} \cr x_{2,3} &=& 1 \pm \sqrt{1^2 +35} \cr x_{2,3} &=& 1\pm \sqrt{36} \cr x_{2,3} &=& 1\pm 6 \cr\cr x_2 &=& 1+6 = 7 \cr x_3 &=& 1-6 = -5 \cr\cr \mathbb{L} &=& \left\{-5;1;7\right\}\end{array}