Question

Determine k for which the roots of the equation 9x² + 2kx + 4 = 0 are equal.

• A. 6
• B. - 6
• C. Both (a) and (b)
• D. None of these

Answer 1

The correct option is C Both (a) and (b)

Let the roots be P and P.

Sum of the roots = 2P = - 2k/9

P = - k/9

and product of roots = P² = 4/9

(- k/9)² = 4/9

k²/81 = 4/9

k² = 36

k = ± 6