What is the vertex of #y=(x-4) (x-2)+x#?
First expand the equation to get it into standard form, then convert into vertex form by completing the square.
The vertex is
A related but very slightly different approach
An alternative approach. It does in fact incorporate part of the process of constructing the vertex equation.
Multiply out the brackets
given that the standard form is
When applying this approach you must have
So in fact
In your question