Prove that the Polynomial f(x) \equal{} x^{4} \plus{} 26x^{3} \plus{} 56x^{2} \plus{} 78x \plus{} 1989 can't be expressed as a product f(x) \equal{} p(x)q(x) , where p(x) and q(x) are both polynomial with integral coefficients and with degree at least 1. algebrapolynomialcalculusintegrationquadraticsmodular arithmeticalgebra unsolved