2ctg²x=3ctg x 2ctg²x-3ctg x=0 ctg x (2ctg x-3)=0 ctg x = 0 x= arcctg 0 + πn, n ∈ Z x=π/2 + πn, n ∈ Z ctgx=1.5 x=arcctg1.5+πn, n ∈ Z