Completed exercise 13-1
Completed Exercise 13-2
Completed Exercise 13-3
Completed Exercise 13-4
Completed Exercise 13-5
Completed Exercise 13-6
Completed Exercise 13-7
Completed Exercise 13-8n
Completed Exercise 14-1
Completed Exercise 14-2
Completed Exercise 14-3
Completed Exercise 15-1
Completed Exercise 15-2
Completed Exercise 15-3
Completed Exercise 15-4
Completed Exercise 15-5