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MathNet 2014 Question 26

Math Olympiad Vault · MathNet 2014

Question 26

Let $x$, $y$ and $z$ be positive real numbers such that $xy + yz + zx = 3xyz$. Prove that
$$
x^2 y + y^2 z + z^2 x \geq 2(x + y + z) - 3
$$