9. Yes

11. No

13. $\{(3,2,-1)\}$

15. $\{(-3,2,4)\}$

17. $\{\begin{array}{lllllll}x& -& y& -& {\displaystyle \frac{3}{2}}z& =& {\displaystyle \frac{1}{2}}\\ & & y& +& z& =& 0\\ & & & & z& =& 1\end{array}$

19. $\{\begin{array}{rcl}x+3y-2z& =& 0\\ y-{\displaystyle \frac{8}{7}}z& =& -{\displaystyle \frac{5}{7}}\\ 0& =& k,k\ne 0\end{array}$

21. $\{(1,-2,3)\}$

23. $\left\{({\displaystyle \frac{30}{11}},-{\displaystyle \frac{8}{11}},-{\displaystyle \frac{1}{4}})\right\}$

25. $\{(1,2,3)\}$

27. $\left\{\left({\displaystyle \frac{35}{18}},{\displaystyle \frac{29}{18}},{\displaystyle \frac{5}{18}}\right)\right\}$

29. Inconsistent

31. $\{(3,-1,2)\}$

33. $\{(2,2,1)\}$

35. $\{(3,-1,1)\}$

37. $\left\{\left(3+{\displaystyle \frac{4}{5}}z,-{\displaystyle \frac{1}{5}}z,z\right)\right\}$

39. $\{(12,-12,4)\}$

41. $\{(1,-1,2)\}$

43. $\{(3,2,-1)\}$

45. $\{(9z-5,-3z-{\displaystyle \frac{1}{6}},z)\}$