1/2(x-2y)+1/3(x+2y)=-1(1) { 1/4(x-2y)-1/5(x+2y)=5(2)
问题描述：
1/2(x-2y)+1/3(x+2y)=-1(1) { 1/4(x-2y)-1/5(x+2y)=5(2)
答
两边乘6
3x-6y+2x+4y=-6
5x-2y=-6 (1)
两边乘20
5x-10y-4x-8y=100
x-18y=100 (2)
(1)*9-(2)
45x-x=-54-100
44x=-154
所以x=-7/2
y=(5x+6)/2=-23/4