Question

The values of k for which the quadratic equation 16x² + 4kx + 9 = 0 has real and equal roots.
A. 6,-1/6
B. 36, – 36
C. 6, – 6
D.3/4,-3/4

Answer 1

The values of k for which the quadratic equation 16x² + 4kx + 9 = 0 has real and equal roots are B. 36, – 36

Answer 2

C. 6, – 6

Step-by-step explanation:

For the quadratic equation 16x² + 4kx + 9 = 0 to have real and equal roots, discriminant should be zero.

d =  b² - 4ac  

b² - 4ac = 0

(4k)² - 4*16*9 = 0

(4k)² = 4*16*9  

(4k)² = 2²*4²*3²

 4k =  2 * 4 * 3

 k = 2 *3

 k = 6

Option C is the answer.