y/3-x+1/6=3 ------(1)2(x-y/2)=3(x+y/18)------(2)(1) 两边同乘6 2y-6x+1=18 2y-6x=17 ---(3)(2) 2x-y=3x+y/6 两边同乘6 12x-6y=18x+y 6x+7y=0 ---(4)(3)+(4) 得 9y=17 y=17/9 代入（4)x=-119/54
