Answer:
see explanation
Step-by-step explanation:
To find the x- intercepts let y = 0, that is
(x - 4)(x + 2) = 0
Equate each factor to zero and solve for x
x - 4 = 0 ⇒ x = 4
x + 2 = 0 ⇒ x = - 2
x- intercepts are x = - 2 and x = 4
The vertex lies on the axis of symmetry which is located at the midpoint of the x- intercepts, thus
= = 1
Substitute x = 1 into the equation for corresponding value of y
y = (1 - 4)(1 + 2) = - 3 × 3 = - 9
vertex = (1, - 9)