Zero of a Function

A zero of a function, also sometimes called a root, is a value in the function domain at which the function equals zero, so that a zero is equivalently a solution to the equation f of x equals zero. A root of a polynomial is a zero of the corresponding polynomial function, and the fundamental theorem of algebra shows that a nonzero polynomial has at most as many roots as its degree, with the number of roots and the degree matching exactly once complex roots are counted with their multiplicities; for example, the degree-two polynomial f of x equal to x squared minus five x plus six factors as the product of x minus two and x minus three, giving the two roots two and three. When a function maps real numbers to real numbers, its zeros are the points where its graph crosses the horizontal axis, also called its x-intercepts. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/