Tg3x меньше или=-1помогите пжл срочно нужно

[latex]tg3x \leq -1\\-\frac{\pi}{2}+\pi n \leq 3x \leq arctg(-1)+\pi n,\ n\in Z\\-\frac{\pi}{2}+\pi n\leq 3x \leq -\frac{\pi}{4}+\pi n,\ n\in Z\\-\frac{\pi}{6}+\frac{\pi n}{3}\leq x \leq -\frac{\pi}{12}+\frac{\pi n}{3},\ n\in Z\\\\x\in[-\frac{\pi}{6}+\frac{\pi n}{3};-\frac{\pi}{12}+\frac{\pi n}{3}],\ n\in Z[/latex]