Explanation:
x(x-4)(x+1) is a 3 degree polynomial in factored form with zeros 0,4 and -1
Just take each zero and change its sign, then stick an x in front of it to get the 3 factors
(x-0)(x-4)(x- -1) = x(x-4)(x+1)
= x(x^2-3x-4)
= f(x) = x^3 -3x^2 -4x
f(0) = 0
f(4) = 64-3(16)-4(4) = 0
f(-1) = -1 -3(-1)^2 -4(-1) = 0
graph the polynomial and it intersects the x axis in 3 places, the origin (0,0), (4,0) and (-1,0)