tg x + 4 = - 3 ctg x | *sin x * cos x
(sin x/ cos x) *sin x * cos x +4sin x * cos x +3 (cos x/ sin x) *sin x * cos x = 0
sin^2 (x) + 4sin x * cos x +3 cos^2 (x) = 0
sin^2 (x) + 4sin x * cos x +3 (1-sin^2 (x)) = 0
-2 sin^2 (x) + 4sin x 8 cos x + 3 = 0