Is the following reasoning correct?
According to the complex conjugate root theorem, the number of complex roots of a polynomial is always equal to its degree.
Since odd degree polynomials have a maximum of 2 turning points, they can have a maximum of 3 real roots. And since even degree polynomials have a maximum of 1 turning point, they can have a maximum of 3 real roots.
Therefore, the maximum number of a real roots a polynomial of any degree can have is 3, all other roots are non-real.