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计 算 题

Dr.Ying's picture
Submitted by Dr.Ying on Wed, 02/15/2017 - 13:59

两个数之和是一非零的实数，且该实数为这两个数之积的4倍。请问：这两个数的倒数之和是多少？
The sum of two nonzero real numbers is 4 times their product. What is the sum of the reciprocals of the two numbers?

(A) 1 (B) 2 (C) 4 (D) 8 (E) 12

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上期答案：
解： 设abcdefghijklmnopqrstu = w
则 （10w+7）*7 = 7*10^21+w
即 69w=7*10^21-49
得 w=101449275362318840579
所以原数为： 1014492753623188405797

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