Steps for Completing the Square Remember that our goal is to add a number to a binomial to make it a perfect-square trinomial. 1. Make sure the leading coefficient is 1. Divide out or factor out the leading coefficient if necessary. 2. To find the number we need to add, we will take the coefficient of x, divide it by 2, and square it. Ex: Fill in the blanks to complete the square and make a perfect square trinomial. a) For x+4x: x+4x+ = x+4x+ 2 b) For x-6x: x-6x+ = x-6x+ - c) For x-8x: r-8x+ = x-8x+