You can put this solution on YOUR website!
I'm suppose to comple the square
Bring it to the standard form i.e, x^2-2xy+y^2
x^2-2.x.(3)+()^2 when compared with the standard form we find in place of y = 3
BY adding (3)^2 the square is completed
Therefore the given expression becomes x^2-6x+9 = (x-3)^2.