Here are the answers to the given questions above.
1. A discriminant of 0 indicates a rational double, which will be -b/2a for a quadratic of the form ax^2 + bx + c. The answer would be C.
2. The quadratic 2x2 + 6x + 3 has two irrational roots. The answer would be option A.
3. The quadratic x2 + 20x + 100 has One Rational Double root. The answer would be C.
4. The possible discriminant of the graph given would be -11. The answer is option B.
5. The possible discriminant of the graph given would be 0. The answer is A.
Hope these answers help.