9. Yes
11. No
13. {(3, 2,−1)}
15. {(−3, 2, 4)}
17. ⎧⎩⎨⎪⎪⎪⎪⎪⎪x−yy−+32zzz===1201
19. ⎧⎩⎨⎪⎪⎪⎪⎪⎪x+3y−2zy−87z0===0−57k, k≠0
21. {(1,−2, 3)}
23. {(3011,−811,−14)}
25. {(1, 2, 3)}
27. {(3518, 2918, 518)}
29. Inconsistent
31. {(3,−1, 2)}
33. {(2, 2, 1)}
35. {(3,−1, 1)}
37. {(3+45z,−15z, z)}
39. {(12,−12, 4)}
41. {(1,−1, 2)}
43. {(3, 2,−1)}
45. {(9z−5,−3z−16, z)}