TeX source:
\begin{array}{crclcl}& \mathbb{D} &=& \mathbb{R} \\\\& 3x^3+6x^2-3x^2-6x &=& 0 \\& 3x^3+3x^2-6x &=& 0 \\& x\cdot\left(3x^2+3x-6\right) &=& 0 &\vert & \text{Satz vom Nullprodukt}\\\text{Faktor 1:} & x_1 &=& 0 \\\\\text{Faktor 2:} & 3x^2+3x-6 &=& 0 &\vert & :3 \\& x^2+x-2 &=& 0 &\vert & \text{p-q-Formel} \\& x_{2,3} &=& -\dfrac{1}{2}\pm\sqrt{\left(\dfrac{1}{2}\right)^2+2} \\\\& x_{2,3} &=& -\dfrac{1}{2}\pm\sqrt{\dfrac{9}{4}} \\\\& x_2 &=& -\dfrac{1}{2}+\dfrac{3}{2} = 1 \\\\& x_3 &=& -\dfrac{1}{2}-\dfrac{3}{2} = -2 \\\\& \mathbb{L} &=& \left\{-2;0;1\right\}\end{array}