Question

For what value of k does equation 9x²+8kx+8 have equal roots?​

Answer 1

Answer:

9x 2+8kx+16=0

Compare given equation with the general form of quadratic equation, which ax 2 +bx+c=0

a=9,b=8k,c=16

Find D:

D=b

2

−4ac

=(8k)

2

−4×9×16

=64k

2

−576

Roots of given equation are equal (given)

So, D=0

64k

2

−576=0

64k

2

=576

k

2

=9

k=±3

Answer k=3,k=−3

Answer 2

Answer:

k= 3 or -3

Step-by-step explanation:

9x2 +8kx +16 = 0

Here,

 a = 9

b = 8k

c =16

It is given that the roots of the equation are real and equal; therefore, we have:

d=0

b∧2-4ac = 0

64k∧2 -576 =0

64k∧2 = 576

k∧2 = 9

k = ±3