8.20 Chapter 2. Second order differential equations. Section 2.14, The method of elimination for systems. Excercises page 258

8.20.1 problem 1
8.20.2 problem 2
8.20.3 problem 3
8.20.4 problem 4
8.20.5 problem 5
8.20.6 problem 6
8.20.7 problem 7
8.20.8 problem 8
8.20.9 problem 9
8.20.10 problem 10
8.20.11 problem 11
8.20.12 problem 12