the velocity-versus-time graph for a basketball player traveling up and down the court in a straight-line path. Find the net displacement of the player for the 10 s shown on the graph.

I am not too sure where to even start. Or even how someone achieves a velocity of -2m/s. Am i supposed to find his displacement on the X axis? if so, am i supposed to use this equation:$\displaystyle X=X_{xo}+V_{xo}+\frac{1}{2}a_{x}t^2$