Question 84
Prove that arbitrary real numbers $a$ and $b$ satisfy the inequality
$$
(a + ab - b^2)^2 + ab^2(a + 2) \geq 0.
$$
When does the equality hold?
$$
(a + ab - b^2)^2 + ab^2(a + 2) \geq 0.
$$
When does the equality hold?
MathNet 2013 Question 84
Math Olympiad Vault · MathNet 2013