Answer:
f(x) = (x - 3)² - 1
Step-by-step explanation:
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
To obtain this form use the method of completing the square
Add/subtract ( half the coefficient of the x- term )² to x² - 6x
f(x) = x² + 2(- 3)x + 9 - 9 + 8
= (x - 3)² - 1
