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