As an object moves with constant acceleration at t0 the

Question

Solve the all parts of given problem:

Problem: As an object moves with constant acceleration. At t=0 the position is x=0. At t=1 the position is x=1 and at t=2 the position is x=5.

Part A: What is the acceleration?

Part B: What is the velocity at t=0?

Part C: What is the average velocity in the first 1.5 seconds?

Please also explain, thank you in advance.