Question

What is a resultant vectors direction?

Answer 1

It depends. I do not know if you are adding vectors in 1D, 2D or even 3D.
In 1D: its direction is along the x axis if its positive, otherwise it is in the opposite direction
In 2D: its direction is along the x or y axis if its component is positive, otherwise it is in the opposite direction
In 3D: its direction is along the x, y or z axis if its component is positive, otherwise it is in the opposite direction

Answer 2

That completely depends on all sizes and all directions of all of the vectors that combined to produce the resultant one.