- TeX source:
- \begin{array}{rclcl} x^2+x-12 &=& 0 \cr x_{1,2} &=& -\dfrac{1}{2} \pm \sqrt{\left(\dfrac{1}{2} \right)^2-\left(-12\right)} \cr\cr x_{1,2} &=& -\dfrac{1}{2} \pm \sqrt{\dfrac{1}{4}+12} \cr\cr x_{1,2} &=& -\dfrac{1}{2} \pm \sqrt{\dfrac{1+48}{4}} \cr\cr x_{1,2} &=& -\dfrac{1}{2} \pm \sqrt{\dfrac{49}{4}} \cr\cr x_{1,2} &=& -\dfrac{1}{2} \pm \dfrac{7}{2} \cr\cr\cr x_1 &=& -\dfrac{1}{2}+\dfrac{7}{2} = 3 \cr\cr x_2 &=& -\dfrac{1}{2} -\dfrac{7}{2} = -4 \cr \cr \mathbb{L} &=& \{-4;3\} \end{array}