题目

解方程组3(x+y)-4(x-y)=4和(x+y)/2+(x-y)/6=1
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提问时间：2020-07-25

答案

(x+y)/2+(x-y)/6=1
x/2+x/6+y/2-y/6=1
2x/3+y/3=1
2x+y=3 (1)
3(x+y)-4(x-y)=4
3x+3y-4x+4y=4
-x+7y=4 (2)
(1)+2*(2)
y+14y=11
y=11/15
x=7y-4=17/15