Question 115
Prove that for all positive real numbers $x, y, z$
$$
\frac{y^2 z}{x} + y^2 + z \geqslant \frac{9y^2 z}{x + y^2 + z}.
$$
$$
\frac{y^2 z}{x} + y^2 + z \geqslant \frac{9y^2 z}{x + y^2 + z}.
$$
MathNet 2018-part-02 — 181 problems (EN–VI) Question 115
Math Olympiad Vault · MathNet 2018-part-02 — 181 problems (EN–VI)