Question

Identify the axis of symmetry and vertex for the quadratic function x2−2x−15.

Axis of Symmetry: x=

Vertex: ( , )

Answer 1

I'll go over a similar example

Let's say we had the function y = x^2 - 8x + 12

It's of the form y = ax^2 + bx + c
a = 1
b = -8
c = 12

The vertex is of the form (h,k) where
h = -b/(2a)
h = -(-8)/(2*1)
h = 4
This is then plugged into the function to get the y coordinate of the vertex
y = x^2 - 8x + 12
y = 4^2 - 8(4) + 12
y = -4

So the vertex is at (h,k) = (4,-4)
The axis of symmetry is x = 4
The axis of symmetry is always passing through the vertex, so the x coordinate of the vertex is the same as the axis of symmetry.

Keep in mind that this is an example, and the values I got earlier aren't the answers to your specific question. Follow these steps to get the answers you need.