Difference between revisions of "2017 JBMO Problems/Problem 2"

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== Problem ==
 
== Problem ==
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Let <math>x,y,z</math> be positive integers such that <math>x\neq y\neq z \neq x</math> .Prove that <cmath>(x+y+z)(xy+yz+zx-2)\geq 9xyz.</cmath>
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When does the equality hold?
  
 
== Solution ==
 
== Solution ==
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{{JBMO box|year=2017|num-b=1|num-a=3|five=}}
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[[Category:Intermediate Algebra Problems]]

Revision as of 15:38, 17 September 2017

Problem

Let $x,y,z$ be positive integers such that $x\neq y\neq z \neq x$ .Prove that \[(x+y+z)(xy+yz+zx-2)\geq 9xyz.\] When does the equality hold?

Solution

See also

2017 JBMO (ProblemsResources)
Preceded by
Problem 1
Followed by
Problem 3
1 2 3 4
All JBMO Problems and Solutions