Here is a question testing concepts of Quadratic equation and nature of roots of quadratic equation. If y = x2 + dx + 9 does not cut the x-axis, then which of the following could be a possible value of d? I. 0 II. -3 III. 9 A. III only B. II only C. I and II only D. II and III only E. I and III only Correct Answer : Choice C. Values that 'd' could take are 0 or … [Read more...] about GMAT PS : Quadratic Equation : Parabola cutting x-axis