# How do you plot the point A (5, -255^\circ) and the point B (3, 60^\circ)?

The coordinates of your points are given in polar form. Basically with this kind of representation the first number represents the distance of your point from the origin. The second is the angle that the line joining the origin and your point makes with the positive $x$ semiaxis.
The dotted lines represent the distances from the origin of $A$ (5 units) and $B$ (3 units).
The negative angle in $A$ is simply described clockwise while the positive angle of $B$ counterclockwise.