Find all the real numbers k that have the following property: For any non-zero real numbers a and b, it is true that at least one of the following numbers: a,b,5a2+6b3is less than or equal to k.
Source: 2019 Peru MO (ONEM) L3 p2 - finals
Tags: algebra, inequalities
Find all the real numbers k that have the following property: For any non-zero real numbers a and b, it is true that at least one of the following numbers: a,b,5a2+6b3is less than or equal to k.