Question 90
Prove that for any positive real numbers $a, b, c$,
$$
2\left(a^{3}+b^{3}+c^{3}+a b c\right) \geq (a+b)(b+c)(c+a).
$$
$$
2\left(a^{3}+b^{3}+c^{3}+a b c\right) \geq (a+b)(b+c)(c+a).
$$
MathNet 2011 Question 90
Math Olympiad Vault · MathNet 2011