Answer:
All of the methods you mentioned can be used to solve quadratic equations. However, some methods may be more efficient than others depending on the specific equation. Here’s a brief overview of when each method might be most useful:
Completing the square can be used to solve any quadratic equation and is a good method to use when the coefficient of the x^2 term is 1.
Factoring can be used when the quadratic equation can be easily factored into two binomials.
The quadratic formula can be used to solve any quadratic equation and is a good method to use when the other methods are difficult to apply.
Taking the square root can be used when the quadratic equation can be written in the form (x-a)^2=b.