TeX source:
\begin{array}{crclll} & x^3-7x &\neq & 0 \\& x\left(x^2-7\right) & \neq & 0\\\text{Faktor 1:} & x &\neq & 0\\\\\text{Faktor 2:} & x^2-7 & \neq & 0 &\vert & +7\\& x^2 &\neq & 7 &\vert &\pm\sqrt{}\\& x &\neq & \pm\sqrt{7}\\\end{array}