Question

If one zero of the polynomial x2-kx-9 is the negative of the other , find the value of k ?

Answer 1

Let α and β be the zeros of the polynomial x^{2} -kx-9

It is given that α=-β

Then, α+β=0

-b/a=0

-(coefficient of x)/coefficient of x²=0

k/1=0

k=0

Answer 2

Let x be zero of the quadratic polynomial, then x is negative of the other
there fore f (x) =f (-x)
given f {x} =
x^2-8ks-9x^2-8kx-9=
x^2+8kx-9-8kx = 8kx
there fore k =0