9 + 6tg(x/6 + 2) = 3
6tg(x/6 + 2) = -6
tg(x/6 + 2) = -1
x/6 + 2 = -π/4 + πk
x/6 = -π/4 - 2 + πk
x = -3π/2 - 12 + 6πk
k∈Z
ОДЗ: tg(x/6 + 2) - существует
cos(x/6 + 2) ≠ 0
x/6 + 2 ≠ π/2 + πk
x/6 ≠ π/2 - 2 + πk
x ≠ 3π - 12 + 6πk
Ответ: -3π/2 - 12 + 6πk, k∈Z