HELP NEEDED

solve the following by completing the square

2x sqaured (dont know to insert power of 2) + 4x - 6

i know i have to divide it by 2 so i get

x sqaured + 2x - 3

but i dont knwo how to work it

also once i have got the answer i have to check it how do i you do this

PLEASE I REALLY NEED HELP!!