①+②,得3x=4,解得x=4/3.
将x=4/3代入②,得4/3-y=1,
解得y=1/3•
②-①,得3x=-3,解得x=-1.
将x=-1代人①,得2×(-1) -3y=4,解得y= -2.
③-②,得5y=28,解得y=28/5.
将y=28/5代入①,得x+2×28/5=9,
解得x=-11/5.
③+④,得6x=24,解得x=4. 把x=4代入②,得3×4-2y= -6,
解得y=9.