TeX Quellcode:

\begin{array}{rclcl} \mathbb{D} &=& \mathbb{R} \cr \cr (2x+3)^2-13 & \geq & (x-5)(x+5)+3x(x-3) \cr 4x^2+12x+9-13 & \geq & x^2-25+3x^2-9x & \vert & -4x^2 +9x-9+13 \cr 21x & \geq & -21 & \vert & :21 \cr x & \geq & -1 \cr \cr \mathbb{L} &=& \lbrack -1;\infty \lbrack \end{array}