用加减法解{2x+2y=8,2x-2y=4.

问题描述:

用加减法解{2x+2y=8,2x-2y=4.
用加减法解{x/3+y/2=0,2(3x-4)-3(y-1)=43.

2x+2y=8
2x-2y=4
两式相减
4y=4,y=1
代入
2x-2=4
x=3