Verified answer

So, the sum of the roots must be zero.

For any quadratic equation

Like : ax

2

+bx+c=0

The sum of roots is given by

a

−b

So, in this equation : 4x

2

−8ka−9

b=−8k & a=4

So, 0=

a

−b

4

−(−8k)

=0

2k=0⇒k=0