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MathNet 2019-part-05 — 184 problems (EN–VI) Question 88

Math Olympiad Vault · MathNet 2019-part-05 — 184 problems (EN–VI)

Question 88

Let $a$, $b$, $c$ be positive real numbers. Prove that
$$
\frac{1}{abc} + 1 \geq 3 \left( \frac{1}{a^2 + b^2 + c^2} + \frac{1}{a + b + c} \right).
$$