A polynomial expression is an algrebraic equation that contains more than two terms. For example, the quadratic equation is x²+4x+5. When you solve this equation and find the roots, the factors would be x=1 and x=-5. In binomial terms, that would be (x-1) and (x+5). Thus, when a polynomial expression is simplified into binomials, that would be
x²+4x+5 = (x-1)(x+5)