Just checked your second question
c) solve 2p^2 + 3p + 1 =1
to get p = 0 (not possible) and p = -3/2
Let me know if I need to elaborate.
d) This one was tricky and I remember being confused by it.
You're meant to substitute your value of p in x2, x3, x4 etc.
Then you'll notice that
x1, x2, x3, x4 = 1, -1/2, 1, -1/2
See the pattern?
So for x2008 (a positve postion) the value will be -1/2
(: