Answer:
g(x) = x(x - 5)(x + 4)
Explanation:
Here the binomial is x + 4, indicating that a root is -4. Note that x is common to all terms of g(x)=x3−x2−20x, so we can immediately write g(x) in partially factored form as
g(x) = x(x^2 - x - 20). Since -20 = -5*4,
g(x) = x(x - 5)(x + 4)