Question 26
Suppose *a*, *b*, *c* are positive real numbers. Prove that
$$
abc(a + b + c) \le a^4 + b^4 + c^4,
$$
with equality iff $a = b = c$.
$$
abc(a + b + c) \le a^4 + b^4 + c^4,
$$
with equality iff $a = b = c$.
MathNet 2026 — Part 05 Question 26
Math Olympiad Vault · MathNet 2026 — Part 05