TeX source:
\begin{array}{rclcl}4 \cdot \dfrac{2x+1}{2x+2} &=& \dfrac{x+1}{4x+2} &\vert& \cdot (4x+2)(2x+2) \cr\cr 4(2x+1)(4x+2) &=& (x+1)(2x+2) \cr 32x^2+32x+8 &=& 2x^2+4x+2 &\vert& -2x^2-4x-2 \cr 30x^2+28x+6 &=& 0 &\vert& :30 \cr x^2+\dfrac{14}{15}x+\dfrac{1}{5} &=& 0 &\vert& \text{p-q-Formel} \cr x_{1,2} &=& -\dfrac{7}{15} \pm \sqrt{\left(\dfrac{7}{15}\right)^2-\dfrac{1}{5}} \cr\cr &=& -\dfrac{7}{15} \pm \sqrt{\dfrac{4}{225}} \cr\cr x_1 &=& -\dfrac{7}{15} + \dfrac{2}{15} = -\dfrac{1}{3} \in\mathbb{D} \cr\cr x_2 &=& -\dfrac{7}{15} - \dfrac{2}{15} = -\dfrac{3}{5} \in\mathbb{D} \cr \cr \mathbb{L} &=& \left\{-\dfrac{3}{5}; -\dfrac{1}{3} \right\} \end{array}