If the discriminant is a positive number, there will be 2 possible solutions. If you replace the entire section of b²-4ac with 16, you will see that the equation becomes; (-b+-√16)/2a --> leading to an answer with the + and another with the -.
If the discriminant is 0, there will be 1 possible solution, (again replace this into the discriminant value) (-b)/2a ---> this formula is used to also find the x coordinates of a vertex, fyi.
If the discriminant is a negative number, there will be no solution (since squareroot of a negative number is not possible)
