Question

If one zero ot the quadratic polynomial f(x)=4x2-8kx-9 is negative of the other find the value of k

Answer 1

F(1)....
4x²-8kx-9
4(1)²-8k(1)-9...
4-8k-9..
8k-13=0
8k=13
k=13/8

Answer 2

Solution:

Let, the two zeroes of the polynomial f(x) = 4x2 – 8kx – 9 be α and − α.

Product of the zeroes = α × − α = – 9

Sum of the zeroes = α + (− α) = – 8k = 0 Since, α – α = 0

⇒ 8k = 0 ⇒ k = 0