The solution method for quadratic equations that depends on the fact that when either factor is zero, the product of the factors is zero quadratic formula 2. a polynomial function of the form y = a 0xn + a 1xn - 1 + a 2xn - 2 + . . + an - 1 + an where a ? 0 and n = 2. factoring method 3. the most useful solution method for quadratic equations, giving the two roots quadratic function