Answer:
vertex = (1, - 9 )
Step-by-step explanation:
The equation of a parabola in vertex form is
f(x) = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
Given
f(x) = x² - 2x - 8
To complete the square
add/ subtract ( half the coefficient of the x- term )² to x² - 2x
f(x) = x² + 2(- 1)x + 1 - 1 - 8
= (x - 1)² - 9 ← in vertex form
with vertex = (1, - 9 )
