Polynomials can be linear (x), quadratic (x2), cubic (x3) and so on, depending on the highest power of the variable.
The number of zeroes of a polynomial is equal to the degree of the polynomial, and there is a well-defined mathematical relationship between the zeroes and the coefficients. Mathematically, if p(x) is a polynomial in x, and if k is any real number, then the value obtained by replacing x by k in p(x) is called the value of p(x) at x = k and is denoted by p(k).
Here, the real number k is said to be a zero of the polynomial of p(x), if p(k) = 0.
Simply put, the zeroes of a polynomial function are the solutions to the equation you get, when you set the polynomial equal to zero.
note :-( the degree of a polynomial is the highest of the degrees of the polynomial's monomials with non-zero coefficients)