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根据3(x+y)-2(x-y)=11,4(x+y)+3(x-y)=9可得出x+y= ,x-y=
人气:341 ℃ 时间:2020-06-06 15:12:55
解答
(x+y)-2(x-y)=11①
4(x+y)+3(x-y)=9②
②-①×4:11(x-y)=-35
(x-y)=-35/11
代入①:(x+y)-2(-35/11)=11
(x+y)=11-70/11
(x+y)=51/11
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