- Since the x-intercepts correspond to the factors of a polynomial function, f(x)=(x+2)(3x−2)(x−c). If the factors of function f are multiplied out, the constant term would be equal to the product of the constant terms in the three factors:(2)(−2)(−c)4cc​=28=28=7​- Multiply the factors of f(x) together:f(x)​=(x+2)(3x−2)(x−7)=(3x2+4x−4)(x−7)=3x3−17x2−32x+28​Since k is the coefficient of the x2-term, k=−17.