I answered before, by completing the square, and told you why the vertex is at (2, -4).
Why don't you just plot the curve yourself?
How to graph this:
Step 0: y=x(x-4)
Step 1: y=x^2-4x
What's next?
Calculator shows vertex at (2,-4)
I asked before, but I'm still stuck. Please help. thanks.
3 answers
I understand why the vertex is there, I just don't understand what you mean by completing the square.
http://www.themathpage.com/alg/complete-the-square.htm#complete