hi, i've got the question

by completing the square, solve the following quadratic equation, giving your answer in surd form

my answer was

but the books answer is

could someone please show me a step by step way of coming to this answer

thanks

ps that last bit was supposed to be the square root sign with the 5 to the right of it, then a division bar beneath them and a 2 underneath that, if someone could tell me how to write that properly that would be appreciated too