Whats the answer to this question show in the picture

Can someone explain to me how to do this problem ?

Amass has an acceleration of 10- 2t. what is its velocity and displacement if it started at x- 4m and the initial velocity was 8m/s? at what time does it have 0 velocity? graph all graphs.

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?