Answer:
option 4
Step-by-step explanation:
Given the x- intercepts say x = a, x = b, x - c then the corresponding factors are
(x - a), (x - b), (x - c) and the polynomial is the product of the factors
Here the x- intercepts are x = 3, x = 0, x = - 1, thus the factors are
(x - 3), (x - 0), (x - (- 1) , that is
(x - 3), x and (x + 1) , then
y = ax(x - 3)(x + 1) ← where a is a multiplier
To find a substitute (1, - 8) into the equation
- 8 = a(1 - 3)(1 + 1) = - 4a ( divide both sides by - 4 )
a = 2, thus
y = 2x(x - 3)(x + 1) ← expand factors using FOIL
= 2x(x² - 2x - 3) ← distribute by 2x
= 2x³ - 4x² - 6x
