What is the vertex form of #y=x^2 - 2x - 15#?
Consider only the right hand side
Consider the constant of 2 inside the brackets
Move the index (power) from
The square of the constant inside the brackets is +1. This produces an error making the equation as it stands different to when we started. So remove it by applying -1. Giving
This adjustment now means that the right hand side intrinsic value is the same as the right hand side was when we started. So at this stage we can quite correctly state that it is equal to y