Решите уравнение tg2x + 2tg2 - 3 = 0

Tg^2x + 2tg x - 3 =0 
tg x = l, x ≠ p/2 +pn, n ∈Z
l^2 + 2 l - 3 = 0
D/4 = 1+3 = 4;
l(1,2) = -1+- 2/1 = -3; 1;
tg x = -3
x= arctg -3  + pm, m ∈ Z
tg x = 1
x= p/4 + pk, k ∈ Z.