Question

Find the value of k , for which the quadratic equations 9x²+3kx+4 has Equal roots ​

Answer 1

comparing this eq with standard form of quadratic equation ax²+bx+c=0

we get a= 9 ,b = 3k ,c = 4

for real and equal roots

D= 0

b²-4ac=0

(3k)² - 4×9 ×4 =0

9k² -144 =0

9k² =144

k² = 144 / 9

k= +- √144/9

k=+- 12/3 = +-4

k= +-4