Polynomials functions are made of terms that have variables which are raised to whole-number exponents (or else the terms are just plain numbers); there are no square roots of variables, no fractional powers, and no variables in the denominator of any fractions.
These are all polynomials: 6x (one term polynomial), 10x + 7 (bi-nomial, degree 1 polynomial), 7x^2 + 2x -6 (tri-nomial, degree 2 polynomial)
The function you are asking about CAN be a polynomial, but in its present form it is NOT. It is currently a rational function (ratio/fraction) See if you can turn it into a polynomial. HINT: can you cancel anything?
To find the zeroes, see if you can draw a graph of the function after you turn it into a polynomial