tg³x+tg²x-3tgx-3=0
tg²x(tg x+1)-3(tgx+1)=0
(tg²x-3)(tgx+1)=0
tgx=±√3 x=π/3+πn x=-π/3+πn
tgx=-1 x=-π/4+πn
Ответ: х=±π/3+πn и -π/4+πn