# If the sum of zeroes of the polynomial x2 - x - k(2x- 1) is zero find the value of k.

2
by garima9cr3

2014-07-04T16:37:15+05:30

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For a quadratic ax² + bx + c = 0
so we know sum of roots = -b /a
product of roots = c/a
let roots of the eq x² - x - k(2x- 1) ⇒ x² - x - 2kx +k ⇒  x² - (1 - 2k)x +k
be x , y
so given x+ y =  0
so (1 - 2k )
/1 = 0
⇒ k = 1/2
hw to mark it best...plz tell...?
when any other person will answer you will automatically given the option to mark best
i dnt knw wher's that option?
thank you
anytym..:)
2014-07-04T17:42:44+05:30
First of all you must know that any quadratic equation can be written as :
Note: This is a very powerful tool. Do remember it.
X^2 -sx+p -----------------(i)
where s is the sum of its roots and p is their product.
On comparing your equation , we get
p=k
s=2k+1