Which formulas might be used to find the velocity based on a position-time graph? check all that apply.

y2 – y1
d/t
x2 – x1
y2 – y1/x2 – x1
? x/t

The formulas which must be used to find the velocity based on a position-time graph, 
1) d/t
2) x/t

velocity = displacement / time.  Given the position-time graph. Find the displacement from the initial and final position and then find the displacement. Then, simply find the velocity by displacement/time