What is the relationship between the zeros of functions and the roots of equations?

What is the relationship between the zeros of functions and the roots of equations?

The abscissa of the zero point of a function is the root of the equation after the function is transformed into an equation
In general, the number of roots of the equation is greater than or equal to the number of zeros of the function, which should be noted, because the equation can be made up of two identical roots, and the two identical roots represent the same zeros in the image
If there is no double root problem, then the number of the two is the same