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

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

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=17/20

2(x-y)/3-(x-y)/4=-1
两边同乘以12,
8(x-y)-3(x-y)=-12
5x-5y=-12 ------------------- (1)

6(x+y)-4(2x-y)=6
6x+6y-4x+4y-6=0
5y-x=3
5y=x+3 ---------------------- (2)

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2(x-y)/3-(x-y)/4=-1
两边同乘以12,
8(x-y)-3(x-y)=-12
5x-5y=-12 ------------------- (1)

6(x+y)-4(2x-y)=6
6x+6y-4x+4y-6=0
5y-x=3
5y=x+3 ---------------------- (2)

把(2)代入(1),
5x-(x+3)=-12
解得,x= -9/4
再代入(2),解得y=3/20

方程的解为x= -9/4 ,y= 3/20

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