[tex] \sqrt{3} tg(3x) + 1 = 0 \\ \sqrt{3} tg(3x) = - 1 \\ tg(3x) = - \frac{1}{ \sqrt{3} } \\ tg(3x) = - \frac{ \sqrt{3} }{3} \\ 3x = - \frac{\pi}{6} + \pi n, \: \: n \: \epsilon \: z\\ x = - \frac{\pi}{18} + \frac{\pi n}{3} \: , \: \: n \: \epsilon \: z[/tex]