Answer:
11. x = -16
12. k = 6
13. x = -19
14. x = -6
15. x = -20
16. Combining like terms isn't to be used on this type of problem. I'm sorry, can you guess on this one?
17. x = 19
18. n = -10
19. b = 11
20. n = 4
21. r = -6
22. n = -4
Again super sorry about question 16 :(