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Simplest way to solve this
- Thread starter lingping7
- Start date
Yes, I'm looking for a shortcut and there is nothing missing in the problem
The answer is -191500 (used a calculator) but how can you do it without actually cubing each number?
a quick toying around with (a - b)3 and (a + b)3 didn't reveal anything
All I can think of (if this is a short cut!):
5^3 9^3 - 5^3 13^3 - 5^3 4^3
= 5^3(9^3 - 13^3 - 4^3)
Thanks Denis!
May not be a short cut, but it is short enough!