Answer:
A, B, and C
Step-by-step explanation:
The discriminant is denoted by b^2 - 4ac, and it can give us information about the roots of the quadratic equation.
It tells us that if:
- b^2 - 4ac < 0 , then there are 0 real solutions; they're all imaginary (involving the letter i, which is the square root of -1)
- b^2 - 4ac = 0 , then there is 1 real solution; this 1 solution has a multiplicity of 2 because the roots of the quadratic are the same number
- b^2 - 4ac > 0 , then there are 2 real solutions; there are no imaginary solutions
Looking at the possible choices, we see that all of A (A, I'm assuming you meant to write "if the discriminant is zero there is one real solution"), B, and C reflect the above properties.
Thus, they're all right.