I am trying to complete the square, just for a quadratic equation, not for a graph. i had no problem with completing the square the first time around, but suddenly, i am getting all the review questions wrong and i dont know why! here is an example:

first, i cleared the co-efficient of the A term and came up with:

(i took half of 2 [which is 1] and squared it [which is 1], added to both sides)

(i rationalized and came up with):

the book says the answer is

where on earth did that -2 come from? all of the problems i have done have the wrong number in front of the plus/minus. i think it has something to do with the co-efficient of the A term, but i dont remember having to do anything with that. i know how to complete the square, i just dont know where that -2 came from. any insight?