18 Chapter 4, Linear Systems. Exercises page 190

18.1 problem 2(a)
18.2 problem 2(b)
18.3 problem 2(c)
18.4 problem 2(d)
18.5 problem 3(a)
18.6 problem 3(b)
18.7 problem 3(c)
18.8 problem 3(d)