1. Show that if p and 2p-1 are both prime, and n=p(2p-1) then n is pseudoprime for 50% of the possible bases b, namely for all b which are quadratic residues modulo (2p-1).

The only thing I could come up with for this one is that it might have something to do with  phi (n)

2. Show that if n is pseudoprime to base b in (Z/nZ)* then n is also pseudoprime to base -b and b^(-1)