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Problems > High School Math > 2004

Prove Composite

Oh, no, not another number theory problem?!


Suppose a²+ab+b²-c²-cd-d²=0, where a, b, c, d are positive integers.

Then I think a+b+c+d is a composite number. It is true? Prove it!



Note: Composite means "not prime." A composite number is a number that has factors other than one and itself.


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