Hints for Homework 9

6.12: Use Theorem 6.5.

6.17: Remember that because r is in U(n), there is a multiplicative
inverse mod n.  Use this fact to show one-to-one and onto.

6.29: This follows from Cayley's Theorem, but be sure to give
a clear explanation.

7.2: Use Lagrange's Theorem, second part.