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MathNet 2023-part-02 — 191 problems (EN–VI) Question 33

Math Olympiad Vault · MathNet 2023-part-02 — 191 problems (EN–VI)

Question 33

Let $x, y, z$ be three non-negative real numbers such that $x \leqslant 1$. Prove that:
$$
x y + y + 2 z \geqslant 4 \sqrt{x y z}
$$