In order to solve a quadratic equation by completing the square, take a quadratic equation and make sure that the coefficient of the first squared term in one. If it is not factor it by pulling the term out to get it to one. Now just write down the first two terms in side a bracket and after it add the third term. Now take the coefficient of the x term and take one half of it and square it and put that number back into the bracket. Now as you added a new number, to cancel it out subtract it from the rest of the outside equation. Now the terms in the brackets can be written as a perfect square. Take the rest of the terms to the right hand side. Now apply square root on both sides and solve the equation for the value of x.