Question

find the value of k for which the quadratic equation x square +2 root 2k x +18 =0

Answer 1

Answer:

k=2

because +2 root 2kx+18=0

Answer 2

The value of k is "± 3".

Step-by-step explanation:

The given quadratic equation is:

$x^{2} +2\sqrt{2} kx+18=0$

To find, the value of k = ?

Here, a = 1, b = $2\sqrt{2} k$ and c = 18

∴$D=b^{2} -4ac$

$=(2\sqrt{2} k)^{2} -4(1)(18)$

$=8k^{2} -72$, the roots are real or equal.

∴$8k^{2}- 72=0$

⇒ $k^{2}=\dfrac{72}{8} =9$

⇒ k = ± 3

Hence, the value of k is ± 3.