Let S be the cube of a prime number, such that S is greater than 504.
Prove that (S-125)(S+125) is evenly divisible by 504.
(In reply to
No Subject by phi)
phi,
I'm not completely sure I follow your reasoning, but in any case, you are assuming that H is greater than 504, whereas the problem referred to S=H^3 being greater than 504. So H only needs to be larger than 7 - e.g. 11. (11^3+5^3)(11^3-5^3)/504=3484 and 13. (13^3+5^3)(13^3-5^3)/504=9546 'work' just as the problem anticipates, but aren't explained by your reasoning.
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Posted by broll
on 2011-05-13 06:36:55 |
re: No Subject
