The question implies you need to find what angles will give a positive solution for x. Only the 1st and 3rd quadrants have a positive answer for x so you need to find these.

Using the symmerty identities (keeping in mind that tan has the preiod of ) the solutions for one revolution of the unit circle will be

All solutions are found then by mulitplying through these soultions into every other revolution of the circle.

So