Solving by factoring and extracting the square roots are techniques that only work for very special quadratic equations. In this section, we will develop a method that will solve any quadratic equation. This technique will be used to develop the quadratic formula.
Complete the square then factor.
Determine the constant that completes the square.
Solve by completing the square:
Step 1: Add or subtract the constant term to the other side.
Step 3: Factor and then apply the square root property.
Solve by extracting roots.
Solve by completing the square.
Caution! Adding 9 inside the parentheses is equivalent to adding 18 here.