17-1

17-2

17-3

17-4

17-5
1 Solutions

17-6

17-7

17-8

17-9

17-10
1 Solutions

17-11

17-12

17-13

17-14

17-15
2 Solutions

17-16

17-17

17-18

17-19

17-20

18-1

18-2

18-3

18-4

18-5
2 Solutions

18-6

18-7

18-8

18-9

18-10
1 Solutions

18-11

18-12

18-13

18-14

18-15
3 Solutions

18-16

18-17

18-18

18-19

18-20
1 Solutions