TeX Quellcode:

\begin{array}{rclll}\dfrac{x^2+8x+16}{x+4} &=& 0 \cr\dfrac{(x+4)^2}{x+4} &=& 0 \cr x+4 &=& 0 &\vert& -4 \cr x &=& -4 \not\in\mathbb{D} \end{array}