When is it most appropriate to use the completing the square method to solve a quadratic equation?

Don't forget to include a ± sign in your equation once you have taken the square root. Next, if the coefficient of the squared term is 1 and the coefficient of the linear (middle) term is even, completing the square is a good method to use. Finally, the quadratic formula will work on any quadratic equation.

Step-by-step explanation:

x² + 4x = 15 can be solved best using the completing the square method.

2x (x-3) = 0 can be best solved using the zero product property.