# Pre-RMO 2014/17

For a natural number $$b$$, let $$N(b)$$ denote the number of natural numbers $$a$$ for which the equation $$x^2 + ax + b = 0$$ has integer roots. What is the smallest value of $$b$$ for which $$N(b) =6$$?

This note is part of the set Pre-RMO 2014

Note by Pranshu Gaba
3 years, 8 months ago

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@Ar Agarwal how is it 60?

- 10 months, 1 week ago

The question becomes in finding the smallest positive integer which has 12 factors(negative).

- 3 years, 8 months ago

We must also check the smallest integer with 11 factors, for example $$2^{10}$$, even that will give $$N(b) = 6$$.

- 3 years, 8 months ago