Answer from cs61c-eo (James McBryan 16730959) for Question 1
c5 = g4 + (p4 . g3) + (p4 . p3 . g2) + (p4 . p3 . p2 . g1) + (p4 . p3 . p2 . p1. g0) + (p4 . p3. p2 . p1 . p0. c0)