Question

find the value of k,if x-2 is a factor of p (x)=x2+2kx+8.

Answer 1

Step-by-step explanation:

Let p (x)=x2+2kx+8.

if x-2 is factor

then,

p(2)=0

p(2)=2x2+2kx2+8=0

4k+12=0

k= -3

Answer 2

Equating the function to 0 we get,

p(x) = 0

=> x²+2kx+8 = 0 ----- (1)

∵ x-2 is a factor of p(x)

∴ one of the roots of (1) is 2

Putting x = 2 in (1) we get,

(2)²+2k(2)+8 = 0

=> 4+4k+8 = 0

=> 4k+12 = 0

=> 4k = -12

=> k = -3