9. $(3,-1)$

11. None of them

13. $(10,-9)$

15. (2, 1)

17. (2, 2)

19. Inconsistent

21. $({\displaystyle \frac{7}{3}},{\displaystyle \frac{14}{3}})$

23. $\{(x,12-3x)\}$

25. Independent

27. Independent

29. Dependent

31. Independent

33. Inconsistent

35. Inconsistent

37. Independent

39. $\left\{\left({\displaystyle \frac{7}{9}},{\displaystyle \frac{23}{9}}\right)\right\}$

41. $\{(3,4)\}$

43. $\varnothing$

45. $\{(-3,5)\}$

47. $\left\{(x,{\displaystyle \frac{1}{2}}(x-5))\right\}$

49. $\{(3,2)\}$

51. $\{(-3,3)\}$

53. $\{(0,-5)\}$

55. $\varnothing$

57. $\left\{\left(x,2-{\displaystyle \frac{2}{3}}x\right)\right\}$

59. $\{(4,1)\}$

61. $\{(-4,2)\}$

63. $\{(2,1)\}$

65. $\{(3,1)\}$

67. $\left\{({\displaystyle \frac{19}{6}},{\displaystyle \frac{5}{4}})\right\}$

69. $\{(4,2)\}$

71. $\{(4,1)\}$

73. $\varnothing$

75. $(x,{\displaystyle \frac{2}{3}}(x-3))$

77. $\left\{(-{\displaystyle \frac{1}{5}},1)\right\}$

79. $\left\{({\displaystyle \frac{3}{2}},{\displaystyle \frac{1}{2}})\right\}$

81. $\{(5,5)\}$

83. $\varnothing$