y = x^2 - 6x + 7
a = 1
b = -6
c = 7
Before you get the A.O.S, you must first solve for the vertex.
The vertex formula is \frac{-b}{2a}
Plug in the numbers:
-(-6) / 2(1)
--6 = 6 and 2*1 = 2
6/2
Vertex (or x) = 3
Now you have to plug in the x in order to find the vertex (or y)
Your equation should now look like this;
y = (3)^2 - 6 (3) +7
Solve each part separately and then add it up...
3^2 = 9
-6 * 3 = -18
+7
9 - 18 + 7
A.O.S (or y) = -2