If f(x) = x2 − 6x + 19, complete the square and determine the minimum or maximum value of the function

minimum value = 10

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 using completing the square

add/subtract ( half the coefficient of the x- term )² to x² - 6x

f(x) = x² + 2(- 3)x + 9 - 9 + 19

     = (x - 3)² + 10 ← in vertex form

with (h, k) = (3, 10 )

To determine maximum or minimum consider the value of a

• If a > 0 then minimum value of k

• If a < 0 then maximum value of k

Here a = 1 > 0, hence minimum value of k = 10

b

step-by-step explanation:

a difference is the result of subtraction. while each of these expressions has subtraction in it, a difference will be the result when subtraction is the last operation applied in the order of operations for the expression. this means subtraction must be outside of the parenthesis. only b has this.