TeX джерело:

\left\{ \begin{array}{l}{x^2} + x > 0,\\{x^2} + x \le 2;\end{array} \right.\;\left\{ \begin{array}{l}{x^2} + x > 0,\\{x^2} + x - 2 \le 0;\end{array} \right.\;\left\{ \begin{array}{l}x(x + 1) > 0,\\(x + 2)(x - 1) \le 0.\end{array} \right.