Question

if x=3 is one root of quadratic equation x2-2k-6=0 then find the vaule of k

Answer 1

x² - 2k - 6 = 0

Given x=3 is a root
So substituting this in above equation,

(3)² - 2k - 6 0
2k = 3
k = 3/2

But i think there is a typing mistake in your equation
It should have been x² - 2kx - 6 = 0

In that case,
(3)² - 2k(3) - 6 = 0
9 - 6k - 6 = 0
k = 1/2

Answer 2

The vaule of k is equal to $\dfrac{3}{2}$.

Step-by-step explanation:

The given quadratic equation $x^2-2k-6=0$

To find, the vaule of k = ?

∴ $x^2-2k-6=0$

Put x = 3 in given quadratic equation, we get

$3^2-2k-6=0$

⇒ 9 - 2k - 6 = 0

⇒ 3 - 2k = 0

⇒ 2k = 3

⇒ k = $\dfrac{3}{2}$

Thus, the vaule of k is equal to $\dfrac{3}{2}$.