Тригонометрические уравнения, 4tg²x-9=0 3tg²x-2tgx=0

Решение
1)  4tg²x-9=0
4tg²x = 9
tg²x = 9/4
a)  tgx = -3/2
x1 = - arctg(3/2) + πn, n∈Z
tgx = 3/2
b)  tgx = 3/2
x2 =  arctg(3/2) + πk, k∈Z
ответ: x1 = - arctg(3/2) + πn, n∈Z;   x2 =  arctg(3/2) + πk, k∈Z

2)  3tg²x-2tgx=0
tgx * (3tgx - 2) = 0
tgx = 0 
x1 = πk, k∈Z
3tgx - 2 = 0
tgx = 2/3
 x2 =  arctg(3/2) + πn, n∈Z
ответ:  x1 = πk, k∈Z:   x2 =  arctg(3/2) + πn, n∈Z