1)ctg3x=-1
2) 1/3sin 3x-1/3=0

1)  ctg(3x) = - 13x = -π/4 + πn, n∈Zx = (-π)/12 + (πn)/3, n∈Z2)  1/3sin 3x - 1/3 = 01/3sin 3x = 1/3sin3x = 13x = π/2 + 2πk, k∈Zx = π/6 + (2πk)/3, k∈Z