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For a,b,d are the positive integers, and d|a means that “a

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by Max@Math Revolution » Thu Feb 11, 2016 10:03 pm
For a,b,d are the positive integers, and d|a means that "a is divisible by d", if d|ab, which of the following must be true?

A. d|a
B. d|b
C. d|2ab
D. d|(a+b)
E. d|(a-b)


* A solution will be posted in two days.
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by Max@Math Revolution » Sun Feb 14, 2016 10:31 pm
For a,b,d are the positive integers, and d|a means that "a is divisible by d", if d|ab, which of the following must be true?

A. d|a
B. d|b
C. d|2ab
D. d|(a+b)
E. d|(a-b)


--> d|ab is ab=dk(k=integer) and also 2ab=2dk can be divided by d.
Therefore, the answer is C.
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