tech support exercises
Error with numberations fixed.
5.3 from book
5.4 from book
5.5 from book
5.7 from book
5.7 from book
5.8 from book
5.9 from book
5.10 from book
5.11 from book
5.12 from book
5.13 from book
5.15 from book
5.18 from book
5.18 from book