Câu hỏi 78
Cho $a, b, c \in \mathbb{R}^+$ thỏa mãn $(a+b)(b+c)(c+a)=8$. Chứng minh rằng
$$
\frac{a+b+c}{3} \geq \sqrt[27]{\frac{a^3+b^3+c^3}{3}}.
$$
$$
\frac{a+b+c}{3} \geq \sqrt[27]{\frac{a^3+b^3+c^3}{3}}.
$$
Math Olympiad Vault · MathNet 2008-part-03 — 165 bài (EN–VI)