From your textbook:

7.1
7.3 Basically replace the NOR gates with NANDS and analyze. Rename inputs appropriately
7.5
7.8

Also consult the circuit for a 74x148 priority encoder and contrast it you your solution for propblem 6.13. Hopefully both are correct, and you should be able to justify both and explain why one approach is better.

You should also look at (but don't hand in) problem 7.4. The answer is probably in your notes (in addition to being in the back of the book)