Question

（x+y）/2- x-y/2=6 3(x+y)=4(x-y)

Answer 1

（x+y）/2- (x-y)/2=6

两边同乘以2,

x+y-x+y=12

2y=12

y=6

把y=6代入:3(x+y)=4(x-y)

3(x+6)=4(x-6)

3x+18=4x-24

x=42

方程组的解为 x=42 ,y=6