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MathNet 2015-part-04 — 191 problems (EN–VI) Question 25

Math Olympiad Vault · MathNet 2015-part-04 — 191 problems (EN–VI)

Question 25

Let $x$, $y$, $z$ be positive real numbers satisfying $x + y + z + xyz = 4$. Show that
$$
\frac{x}{\sqrt{2y+3z}} + \frac{y}{\sqrt{2z+3x}} + \frac{z}{\sqrt{2x+3y}} \ge \frac{1}{\sqrt{5}}(x+y+z).
$$