Question

The value(s) of k for which the quadratic equation 2x2 + kx + 2 = 0 has
equal roots, is
(A) 4
(B)
(C)
(D)
+4
- 4
0​

Answer 1

Answer:

option B

Step-by-step explanation:

k^2 -4(2)(2) =0

k^2 -16=0

k^2=16

k=(+ or -)4

Answer 2

The value of k is $\pm 4$

Step-by-step explanation:

Given quadratic equation is $2x^2+kx+2=0$ has equal roots

To find the value of k in the given quadratic equation :

• Since the given quadratic equation has equal roots
• Then for quadratic equation $ax^2+bx+c=0$ we have that
• $D=b^2-4ac=0$
• From the given quadratic equation we have a=2 , b=k and c=2

Now substitute the values in  $D=b^2-4ac=0$ we get

• $(k)^2-4(2)(2)=0$
• $k^2-16=0$
• $k^2=16$
• $k=\pm 4$
• Therefore the value of k is $\pm 4$

The option $\pm 4$ is correct