Question

Find the value of ‘p’ for which the roots of the following equation are real and equal:

4x² + px + 9 = 0

Answer 1

Given:

4x² + px + 9 = 0

For a quadratic equation ax² + bx + c = 0, the discriminant is:

D = b² − 4ac

D = 0

Here:

a = 4

b = p

c = 9

D = p² − 4(4) (9)

= p² − 144

p² − 144 = 0

⇒ p² = 144

⇒ p = `±sqrt144`​

= ±12

p = 12 or p = −12