TeX Quellcode:

\begin{array}{rclcll}0 &=& 20\sqrt{2x-15}-15 &\vert& +15 \\15 &=& 20\sqrt{2x-15} &\vert& :20 \\\dfrac{3}{4} &=& \sqrt{2x-15} &\vert& ()^2 \\\\\left(\dfrac{3}{4}\right)^2 &=& 2x-15 &\vert& +15 \\\\\dfrac{249}{16} &=& 2x &\vert & :2 \\\\x &=& \dfrac{249}{32}\approx 7{,}78\;\in\;\mathbb{D}\\\end{array}