81.4 Chapter IV. Ordinary linear differential equations with constant coefficients. Exercises at page 48

81.4.1 problem 1
81.4.2 problem 2
81.4.3 problem 3
81.4.4 problem 4
81.4.5 problem 5
81.4.6 problem 6
81.4.7 problem 7
81.4.8 problem 8
81.4.9 problem 9