1. 
+ -4 - 0 + 2 - 9 +
x ∈ [-4; 0] ∪ [2; 9]
2.
- -2 + -3 - 5 +
x ∈ [-2; -3] ∪ [5; ∞)
3. 
0\\" alt="\frac{6}{x^2 - 6x} < \frac{1}{x - 6}\\\frac{6 - x}{x(x-6)} < 0\\\frac{(x - 6)}{(x - 0)(x-6)} > 0\\" align="absmiddle" class="latex-formula">
- 0 + 6 +
x ∈ (0;6) ∪ (6; ∞)
4. 
+ -2 - 1/2 + 1 +
x ∈ [-2; 1/2]