√(3)tg(-4x-(4/7)п) = -3
tg(-4x-(4/7)п) = -3 / √3
tg(-4x-(4/7)п) = -3 *√3 / (√3*√3)
tg(-4x-(4/7)п) = -√3
-4x-(4/7)п = arc tg(-√3)
-4x-(4/7)п = (-π/3) + πk, k∈Z.
-4x = (-π/3) + (4π/7) + πk
x = (-π/(-4*3) + (4π/(-4*7) + (π/-4)*k
x = π/12 - π/7 - (π/4)*k
x = (-5/84)*π - (π/4)*k.
Можно вынести общий множитель за скобки:
k∈Z.