Complete square!
Vertex form is (x-h)^2+k
meaning that the vertex is located at (h,k).
[tex]y=x^2-6x+18[/tex]
[tex]=(x^2-2(3x)+9)+9[/tex] 3^2=9
[tex]=(x-3)^2+9[/tex]
vertex form, h=3, k=9, vertex is located at (3,9)
Edited 2018-03-18
There was a suggestion to explain the completion of square as
x^2-6x=(x-3)^2-9.
However, this does not show where the (x-3) come from.
If this is a better explanation for any or all of you, here it is.
