二元一次方程2(x-y)/3-x-y/4=-1 6(x+y)-4(2x-y)=6

问题描述:

二元一次方程2(x-y)/3-x-y/4=-1 6(x+y)-4(2x-y)=6

2(x-y)/3-x-y/4=-1
两边乘12
8x-8y-3x+3y=12
5x-5y=12 (1)
6(x+y)-4(2x-y)=6
6x+6y-8x+4y=2
x-5y=-1 (2)
(1)-(2)
4x=13
所以x=13/4
y=(x+1)/5=17/20x呢最后两行。你后补的吧??