二元一次方程组：y/3 - x+1/6 = 3 2 ( x - y/2) = 3( x + y/18 )

y/3-(x+1)/6=3 两边乘以6 得 2y-(x+1)=18
x-2y+19=0 两边乘以6
6x-12y+19*6=0(1)
2(x-y/2)=3(x+y/18) 化简得 2x-y=3x+y/6 两边乘以6 得12x-6y=18x+y
6x+7y=0 (2)
(1)-(2)
-19y+19*6=0
y=6
带回(2)
6x+7*6=0
x=-7
再问： 帮个忙，用加减法解