////////////////////////////////////////
Получилось X=4 т.к 3^4=81
tg3x= -2+<span>√3
3x= arctg(-2+<span>√3) + пk
</span>3x= -arctg(2-<span>√3) + пk
</span>x = -1/3 * arctg(2-<span>√3) + пk/3
</span>
tg3x= -2-<span>√3
</span>3x= arctg(-2-<span>√3) + пk
</span>3x= -arctg(2+<span>√3) + пk
</span>x = -1/3 * arctg (2+<span>√3) + пk
</span>Ответ: -1/3 * arctg (2+-<span>√3) + пk</span> </span>