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