The quadratic equation 4x2 4kx 9 0 k 0 has exactly one s

The quadratic equation 4x^2 + 4kx + 9 = 0, k > 0 has exactly one solution for x. Find the value of k.

Solution

4x^2 + 4kx + 9 = 0

if quadratic equation has only one solution then its discriminant = 0

b^2 - 4ac = 0

a =4 , b = 4k , c = 9

(4k)^2 - 4 (4)(9) = 0

16k^2 - 144 = 0

16k^2 = 144

k^2 = 144 / 16

k^2 = 9

k = 3