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【OG20-P167-138题】
If x and y are positive numbers such that x + y = 1, which of the following could be the value of 100x + 200y?
I. 80
II. 140
III. 199
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题目:假设x、y都是正数,并且x+y=1,那么以下哪个数字可能是100x+200y的值?
解答:1. x+y=1,则100x+200y=100(x+y)+100y=100+100y=100(1+y),
2. 已知x>0,y>0, 所以1+y>1,即100x+200y>100,因此140和199是可能的值,答案为II和III。
题目讨论 (3条评论)

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180687pkqh
100x+200y=100x+100y+100y=100(x+y)+100y=100+100y 0
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0 回复 2022-03-30 16:12:39
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Caroline_wyzh
画图,xy都是正数,在x+y=1中可得0
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0 回复 2021-12-30 22:22:41
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999+
这道题怎么做哇 有uu解析一下吗
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0 回复 2021-10-16 21:25:51