There are several comments, including one at each variable declaration and one at each function definition.
The graph is correctly sketched and appears as a curve.
The input allows for polynomials of any degree up to at least 5.
Every x intercept that is calculated is correct to the nearest whole number.
Every x intercept is calculated and is correct to the nearest hundredth.
The equation is easy for the user to enter and to read.
The project is enhanced by an additional feature or styling of your own.