8 Chapter 4, Section 4.1. Basic theory of linear differential equations. Exercises page 113

8.1 problem 1 (a)
8.2 problem 1 (b)
8.3 problem 2
8.4 problem 4 (a)
8.5 problem 8
8.6 problem 9
8.7 problem 10
8.8 problem 11
8.9 problem 12
8.10 problem 13