Answer:
The value of k is -4. Third choice
Step-by-step explanation:
The Polynomial Remainder Theorem
It states that the remainder of the division of a polynomial f(x) by (x-a) is equal to f(a).
We are given the polynomial:
![p(x)= x^3+kx^2+x+6](https://img.qammunity.org/2021/formulas/physics/high-school/iruq9rze9hgkxbgbgnyjt9uwjgzxsdgddc.png)
And we also know x+1 is a factor of p(x). If x+1 is a factor of p(x), then the remainder of the division of p(x) by x+1 is zero.
Applying the remainder theorem for a = -1:
![p(-1)= (-1)^3+k(-1)^2+(-1)+6=0](https://img.qammunity.org/2021/formulas/physics/high-school/opxona0ncx3iz9swkgt0cpaiiiuuk5jfre.png)
![-1 + k - 1 + 6 = 0](https://img.qammunity.org/2021/formulas/physics/high-school/fm4qpt5ectepnp9e5j0bl3u3jkmzyg4le0.png)
Solving for k:
![k = 1 + 1 - 6](https://img.qammunity.org/2021/formulas/physics/high-school/oqo4grsjcarum7hzvl2c30ns17izjj487n.png)
![\boxed{k = -4}](https://img.qammunity.org/2021/formulas/physics/high-school/pc0wggebk9515bzsi8dm391muri1bwu2l1.png)
The value of k is -4. Third choice