Question

Q-6 For what value of K, the equation
9x²+ Kx + 1 = 0 had equal roots​

Answer 1

$\green{ \underbrace{ \bold{Required \: Answer}}}$

The given equation if ,

$9x2+kx+1=0$

comparing with,

$ax2+bx+c=0$

here a=9, b=k , c=1,

$△ = b2−4ac \\ </p><p>= k2−4(9)(1) \\ </p><p>= k2−36$

The roots are equal so △ must be zero.

$∴ = k2−36=0</p><p>= (x+6)(x−6)=0</p><p>=x+6=0 or x−6=0</p><p>∴ k=−6 or k=6$

Hence, k= -6 or k=6✅

Hope this helps you✌