Polynomial functions have a
finite number of addends, each of which is a
known number times a variable raised to a power that is a
known non-negative integer. The degree of a polynomial is the highest power where the multiplying number is not zero.
[MATH]f(x) = - 3x + 4[/MATH] is a polynomial of degree 1.
[MATH]f(x) = 2x^4 - 3x + 4[/MATH] is a polynomial of degree 4.
The zeroes of f(x) are the values of x such that f(x) = 0. Polynomials of degree higher than 4 may not have zeroes expressible solely in radicals. Even the meaning of the term "a solution by radicals" is a bit comples, but polynomials of degree 5 and higher are not
generally solvable by radicals.
The Riemann Hypothesis is not about a polynomial function at all, but about a much more complex function. It involves an
infinite number of addends, each of which is a known number raised to the
power of a variable, which variable need not even be a real number. We have gone from the finite to the infinite and are no longer talking about known non-negative integer powers.
I have a suggestion for anyone not a mathematician (such as me) when confronted with a problem that professional mathematicians have not been able to solve in decades. If you think you have a simple solution, perhaps you have misunderstood the problem because the mathematicians would almost certainly have stumbled on a simple solution at some time over the last 150 years.