[Antidifferentiation] Find initial position given information about acceleration, time and position

A body moves in a straight line with an acceleration of 10 m/s^2 . If after 2s it passes through the origin (O) and after 3s it is 25m from O, find its initial position relative to O.

I'm not sure how to write out the acceleration as a formula, so that I can use anti-differentiation to find the velocity and position formulae. Any help is appreciated.