Решим уравнение:
$$Sin(\frac{x}{2} - \frac{\pi}{6}) + 1 = 0$$
$$Sin(\frac{x}{2} - \frac{\pi}{6}) = -1$$
$$\frac{x}{2} - \frac{\pi}{6} = arcsin(-1) + 2\pi k, k \in Z$$
$$\frac{x}{2} - \frac{\pi}{6} = -\frac{\pi}{2} + 2\pi k, k \in Z$$
$$\frac{x}{2} = -\frac{\pi}{2} + \frac{\pi}{6} + 2\pi k, k \in Z$$
$$\frac{x}{2} = -\frac{3\pi}{6} + \frac{\pi}{6} + 2\pi k, k \in Z$$
$$\frac{x}{2} = -\frac{2\pi}{6} + 2\pi k, k \in Z$$
$$\frac{x}{2} = -\frac{\pi}{3} + 2\pi k, k \in Z$$
$$x = -\frac{2\pi}{3} + 4\pi k, k \in Z$$
Ответ: $$x = -\frac{2\pi}{3} + 4\pi k, k \in Z$$