DIRECTIONS for the question: Solve the following question and mark the best possible option.
The sum of the roots of a quadratic equation is 4 and the product of the roots is – 21. What is the quadratic equation?
A)
x2 + 4x + 12 = 0
B)
x2 – 4x + 12 = 0
C)
x2 + 4x + 24 = 0
D)
x2 – 4x – 21 = 0
E)
None of these
D
If S is the sum of roots and P is the product of roots then the equation is x2 – Sx +P = 0. In this case S = 4 and P = – 21. So the equation is x2 – 4x – 21 = 0.
