What is Polynomial?

The powers must be $0, 1, 2, 3, \dots$, never negative or fractional. The degree is the highest power. A polynomial in one variable uses only one letter, for example $x$. $x^2 + \sqrt{x}$ and $\dfrac{1}{x} + 2$ are not polynomials. Polynomials of degree 1, 2 and 3 are called linear, quadratic and cubic. The zeros of a polynomial are the values of the variable that make it equal to zero.