58.9 Chapter 4, Section 4.1. Basic theory of linear differential equations. Exercises page 124

58.9.1 problem 1
58.9.2 problem 2
58.9.3 problem 3
58.9.4 problem 4
58.9.5 problem 5
58.9.6 problem 6
58.9.7 problem 8
58.9.8 problem 9