1)

[tex](x - 1)(x + 2) > 0 \\ + + + ( - 2) - - - (1) + + + \\ otvet \: \: \: x \: \epsilon \: ( - \propto; \: - 2)U(1; \: + \propto)[/tex]

2)

[tex] {x}^{2} + 7x \leqslant 0 \\ x(x + 7) \leqslant 0 \\ + + + [ - 7] - - - [0] + + + \\ otvet \: \: \: x \:\epsilon \: [ - 7; \: 0][/tex]

3)

[tex] \frac{ {x}^{2} + x }{x - 3} < 0 \\ \frac{x(x + 1)}{x - 3} < 0 \\ x(x + 1)(x - 3) < 0 \\ - - - ( - 1) + + + (0) - - - (3) + + + \\ otvet \: \: \: x \:\epsilon \: ( - \propto; \: - 1)U(0; \: 3)[/tex]