Question

If x2 + 2 kx + 4 = 0 has a root x = 2 , then the value of k is ?
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Answer 1

Step-by-step explanation:

If x^2 + 2kx + 4 = 0 has a root x = 2, then find the value of k.

Answer 2

Step-by-step explanation:

Given: polynomial x 2−kx+4=0, has equal real roots

To find the value of k

sol: A quadratic equation has equal real roots if the discriminant b 2−4ac=0

x 2−kx+4=0 is of form ax

2+bx+c=0

∴a=1,b=−k,c=4

Hence th discriminant is

(−k) 2−4(1)(4)=0

⟹k 2 −16=0

k=±4