Since I am not sure what you are asking, I am just going to throw a bunch of information at you and hope that the answer you are seeking is present.
1) The slope is equal to the velocity at a given time. In other words, find the velocity and evaluate at it at that specific value of time.
2) Velocity = acceleration x time, assuming the acceleration is constant.
3) Velocity = area under the curve of acceleration, evaluated from the start time to the end time.
Hope this helps.