The document discusses completing the square, which is a process for rewriting quadratic expressions in the form (x - h)2 + k. It provides examples of using completing the square to solve quadratic equations by making the left side a perfect square. The key steps are: 1) write the equation in the form ax2 + bx + c, 2) take half the coefficient of x and square it, 3) add this quantity to both sides, 4) group the left side as a squared binomial, 5) take the square root of both sides. Completing the square allows quadratic equations to be solved using the square root property and written in vertex form.