-2 [ x^2 - (x/2) - (3/2) ] = -2 [ x^2 - (x/2) + (1/4)^2 - (3/2) - (1/4)^2 ]
gives =-2 { [ x - (1/4) ]^2 - (25/16) } => -2 [ x-(1/4) ]^2 + (25/8)
You asked a similar question and were given detailed replies here: http://www.mathhelpforum.com/math-he...re-183638.html
You're meant to learn something from the help you get, especially since a lot of time and effort has been invested in providing that help.
Also, from your other posts you are studying calculus. Basic algebra like this is something you are expected to have learnt and mastered before studying calculus. Given the appearance of your current situation, you are advised to go back and review your class notes or textbook, and probably to get remedial help from your instructor.