Question

What is the vertex of the graph of the function below? y = x2 - 8x + 12 A. (-2, 0) B. (-4, -4) C. (-4, 0) D. (-2, -4)

Answer 1

To find the vertex of the parabola, we need to write it in a vertex form.

y=x² - 8x +12 

1) complete the square

y=x² - 8x +12 
y = x² -2*4x + 4² - 4² +12
y=(x-4)²  -16 +12

2) calculate and write a vertex
y=(x-4)²  -16 +12
 y=(x-4)²  - 4

(x-4)           -----     x- coordinate of the vertex x=4
 y=(x-4)²  - 4    -------y- coordinate of the vertex  y = -   4 
  
Vertex is (4, -4).
Answer is (4, -4).  No correct answer is given in choices.