For this case we have that by definition, the quadratic formula is:
A quadratic equation is of the form:
Option A: This equation can be solved without the quadratic formula
Option B:
This equation is not as easy to solve by factoring or as option A. We can use the quadratic formula.
Option C:
Similarly, this equation can be solved with the quadratic formula
Option D:
In this factored equation we can see that the roots are
Answer:
Option B, C