(1)0.5x+2y等于-1(2)0.5x-7y等于9的解

问题描述:

(1)0.5x+2y等于-1(2)0.5x-7y等于9的解

(1)-(2)
0.5x+2y-0.5x+7y=-1-9
9y=-10
y=-10/9
x=2(-1-2y)=22/9