Answer this and I'll mark you the brainliest if the polynomial x^4-3x^3-6x^2+kx-16 is exactly divisible by x^2+4x+3,find the value of k

k = -18.

But See below.

Step-by-step explanation:

f(x) =  x^4 - 3x^3 - 6x^2 + kx - 16

If  x^2 + 3x + 2 is a factor then so is (x + 1) and (x + 2) as

x^2 + 3x + 2 = (x + 1)(x + 2)

So by the Factor Theorem f(-1) = 0:

f(-1) = (-1)^4 - 3(-1)^3 - 6(-1)^2 - 1k - 16 = 0

1 + 3 - 6 - k - 16 = 0

-18 - k = 0

k =  -18.

Checking:

f(-2) =   (-2)^4 - 3(-2)^3 - 6(-2)^2 - 18(-2) - 16

=  16 + 24 - 24 + 36 - 16 = 36   (NOT 0).