Let n be a nonnegative integer and let a_n,a_n-1,...,a₂,a₁,a₀ be real numbers with a_n0. The function given by :

f(x)= a_nxⁿ+a_n-1x^n-1+...+a₂x²+a₁x+a₀

is called a polynomial function of x with degree n.

Polynomial functions are classified by degree:

• A constant function f(x)=c with c0 has degree 0.
• A linear function f(x)=ax+b with a0 has degree 1.
• A quadratic function f(x)=ax²+bx+c with a0 has degree 2.