Question

if the sum of the zeroes of the quadratic polynomial 4x^2-8x-9 is negative of the other find the value of k
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Answer 1

The question says one root is negative of others.

So, the sum of the roots must be zero.

For any quadratic equation

Like : ax2+bx+c=0

The sum of roots is given by a−b

So, in this equation : 4x2−8ka−9

b=−8k & a=4

So, 0=a−b

4−(−8k)=0

2k=0⇒k=0