Answer:
y = 3(x - 1)(x + 5)(x + 2)
Step-by-step explanation:
Given points: (1, 0) (-5, 0) (-2, 0) (-4, 30)
x-intercepts are when y = 0
Therefore, the x-intercepts are x = 1, x = -5 and x = -2
So (x - 1), (x + 5) and (x + 2) are all factors of the polynomial.
Therefore, the equation of the polynomial is:
y = a(x - 1)(x + 5)(x + 2) where a is a constant to be found
To find the constant a, input the point (-4, 30) into the equation and solve:
⇒ a(-4 - 1)(-4 + 5)(-4 + 2) = 30
⇒ a(-5)(1)(-2) = 30
⇒ 10a = 30
⇒ a = 3
Therefore, the equation of the polynomial is:
y = 3(x - 1)(x + 5)(x + 2)
