Consider the quadratic function:

f (x) = x2 - 8x - 9

Vertex: (negative b Over 2a, f (negative b Over 2 a))

What is the vertex of the function? (,)

(4, - 25)

Step-by-step explanation:

The function is put into this form: f (x) = Ax^2 + Bx + C

In the equation x^2 - 8x - 9, A is 1, B is - 8 and C is - 9

The negatives cancel for negative B so 8 is positive.

8 / 2 (1) = 4

Now we plug 4 into the function as x to find the y value

4^2 - 8 (4) - 9

-25