In mathematics, the Riemann hypothesis is a conjecture that the Riemann zeta function has its zeros only at the negative even integers and complex numbers with real part 12. These are called its trivial zeros. However, the negative even integers are not the only values for which the zeta function is zero.10 of the Toughest Math Problems Ever Solved. Earlier this week, a math puzzle that had stumped mathematicians for decades was finally solved. It's called a Diophantine Equation, and it's sometimes known as the "summing of three cubes": Find x, y, and z such that x³+y³+z³=k, for each k from 1 to 100.