88.18 Chapter 5. Special Techniques for Linear Equations. Exercises at page 133

88.18.1 problem 1
88.18.2 problem 2
88.18.3 problem 3
88.18.4 problem 4
88.18.5 problem 5
88.18.6 problem 7 (a)
88.18.7 problem 7 (b)
88.18.8 problem 8 (a)
88.18.9 problem 8 (b)