To use the complete the square technique, the coefficient of must be 1.
So we can rewrite the equation
Now this is where we apply this technique.
You need to introduce this new term into the equation.
Take the coefficient of the x term, divide by 2, then square that quantity:
In essence, we now add "zero" to the equation:
becomes a perfect square:
So our equation now takes on the general form .
We have "completed the square".
Does this make sense?