In school we're learning to use the quadratic formula. I understand how to use it and what its applications are, but I don't understand why sometime it's okay to simplify and sometimes it's not. For example, I got the result (-2 ± 2 square root of 6)/2. According to the back of my book, this is the correct answer. I would normally just divide the whole thing by two and therefore be left with - 1 ± square root of 6, but this gives me a different answer. So, my question is, when do I reduce and are there rules to it?