Online calculator to determine sum and product of roots of cubic equation. A root is where the polynomial is equal to zero. In general, sum of the root gives (−b/a) and product of the root gives (z/a), for even degree polynomials like quadratic equations and (−z/a) for odd degree polynomials like cubic equations. Use the below online sum and product of cubic roots calculator and determine the cubic equation with real constants given in the input below.