Question

If 9x2+kx+1=0 has equal roots ,find the value of k

Answer 1

Solution:

Compare 9x²+kx+1=0 with

ax²+bx+c=0 ,we get

a=9, b=k, c = 1

Now ,

Discreminant (D) = 0

[ Since , roots are equal ]

=> b²-4ac = 0

=> k²-4×9×1 = 0

=> k²-36=0

=> k² = 36

=> k = ±√36

=> k = ± 6

Therefore,

k = ±6

••••

Answer 2

Step-by-step explanation:

9x²+kx+1

(ans) k=+ or - 6