TeX source:
\begin{array}{rclcll} -\dfrac{23}{20} &=& \dfrac{x^2-2}{x^2+4}-2 & \vert & +2 \cr\cr \dfrac{17}{20} &=& \dfrac{x^2-2}{x^2+4} &\vert& \cdot \left(x^2+4\right) \cr\cr \dfrac{17}{20}\cdot \left(x^2+4\right) &=& x^2-2 \cr\cr\dfrac{17}{20}x^2+\dfrac{17}{5} &=& x^2-2 & \vert & -x^2-\dfrac{17}{5} \cr\cr -\dfrac{3}{20}x^2 &=& -\dfrac{27}{5} &\vert& :\left(-\dfrac{3}{20}\right) \cr x^2 &=& 36 &\vert& \pm\sqrt{} \cr\cr x_1 &=& 6\in\mathbb{D} & & \rightarrow \quad P_2\left(6 \mid -\dfrac{23}{20}\right) \cr x_2 &=& -6\in\mathbb{D} & & \rightarrow \quad P_3\left(-6 \mid -\dfrac{23}{20}\right)\end{array}