1.) write f(x) = x2 - 6x + 8 in vertex form

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

the answer is 99.