Question

find value of k in quadratic equation 4x²+ kx +9=0​

Answer 1

Answer:

k=12

Step-by-step explanation:

a=4

b=k

c=9

D=0

b²-4ac=0

(k)²-4×4×9=0

k²-144=0

k²=144

k=√144

k=12

k=12

Answer 2

Given :

4x²+ kx +9=0

To find :

Value of K

Solution :

4x²+ kx + 9= 0

ax²+ bx + c =

For one solution b² - 4ac = 0

a = 4 , b = k , c = 9

b² - 4ac = 0 ...............(formula)

(k)² - 4 x 4 x 9= 0

(k)² - 144 = 0

k = 12

put k = 12 value in equation

4x²+ 12x + 9 = 0

= 4x²+ 6x + 6x + 9 = 0

= 2x(2x + 3) + 3(2x + 3) = 0

= (2x+3)(2x+3) = 0

= x = -3/2 or x = 3/2