TeX source:
\begin{array}{crclcl} & \mathbb{D} &=& \mathbb{R} \cr\cr & \dfrac{1}{2}x^3+\dfrac{13}{2}x^2-2x &=& 26 & \vert & \cdot 2 \cr & x^3+13x^2-4x &=& 52 & \vert & -52 \cr & x^3+13x^2-4x-52 &=& 0 \end{array}