A polynomial function is a function whose rule contains a polynomial. For example, p(x)=x2−17andq(x)=3x4−x+9, p(x)=x^2-17 \quad \text{and} \quad q(x)=3x^4-x+9, p(x)=x2−17andq(x)=3x4−x+9, are both polynomial functions. Unless explicitly stated, the domain of a polynomial function is all real numbers.