3(x加y)减4(x减y)等于4,2分之x加y加6分之x减y等于1。解二元一次方程

2025-04-08 04:43:48
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回答1:

3(x+y)-4(x-y)=4 ......(1)
(x+y)/2+(x-y)/6=1 ......(2)
(2)两边同乘以6得:
3(x+y)+(x-y)=6 ......(3)
(3)-(1)得:
5(x-y)=2
x-y=2/5 ......(4)
(3)×4+(1)得:
15(x+y)=28
x+y=28/15 ......(5)
(4)+(5)得:
2x=34/15
x=17/15
(4)-(5)得:
2y=22/15
y=11/15