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How many integers n>1 are there such that xn-x+a is reducible over the rationals(it can be factored into at least two nontrivial rational factors) for some positive integer a?
(No Solution Yet, 0 Comments) Submitted on 2019-03-21 by Danish Ahmed Khan   
Difficulty: 3 of 5 Bonus: Mental Arithmetic (in Numbers) Rating: 3.33
I can multiply any three-digit number by 1667 in my head, usually in less than 10 seconds.

Also, to make it even more impressive, I come up with the digits of the result in proper order (not in reverse!)

How can I do this?

(Solution Posted, 20 Comments) Submitted on 2003-10-05 by nellie   
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Posted on 2019-03-13 by Danish Ahmed Khan (No Solution Yet, 1 Comments)

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