Compute all given parts of following problem:

Problem: A lunar lander is descending toward the moon's surface. Until the lander reaches the surface, its height above the surface of the moon is given by y(t)=b - ct+dt², where b = 710m is the initial height of the lander above the surface, c = 61.0m/s , and d = 1.00m/s².

Part A: What is the initial velocity of the lander, at t = 0?

Part B: What is the velocity of the lander just before it reaches the lunar surface?

Please use great detail in explaining the solution. Thanks.