Difference between revisions of "1991 OIM Problems/Problem 5"

(Created page with "== Problem == Let <math>P(x,y) = 2x^2 - 6xy + 5y^2</math>. We will say that an integer <math>a</math> is a value of <math>P</math> if there exist integers <math>b</math> and <...")
 
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== Solution ==
 
== Solution ==
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* Note.  I actually competed at this event in Argentina when I was in High School representing Puerto Rico.  I have no idea what I did on this one nor how many points they gave me.
 
{{solution}}
 
{{solution}}
  
 
== See also ==
 
== See also ==
 
https://www.oma.org.ar/enunciados/ibe6.htm
 
https://www.oma.org.ar/enunciados/ibe6.htm

Revision as of 17:27, 14 December 2023

Problem

Let $P(x,y) = 2x^2 - 6xy + 5y^2$. We will say that an integer $a$ is a value of $P$ if there exist integers $b$ and $c$ such that $a=P(b,c)$.

i. Determine how many elements of {1, 2, 3, ... ,100} are values of $P$.

ii. Prove that the product of values of $P$ is a value of $P$.

~translated into English by Tomas Diaz. ~orders@tomasdiaz.com

Solution

  • Note. I actually competed at this event in Argentina when I was in High School representing Puerto Rico. I have no idea what I did on this one nor how many points they gave me.

This problem needs a solution. If you have a solution for it, please help us out by adding it.

See also

https://www.oma.org.ar/enunciados/ibe6.htm