If x+8 is a factor then it follows that;
x + 8 = 0
x = - 8
Substituting -8 for x in the function and equating f(x) to zero, we have,
[tex]\begin{gathered} (-8)^3+4(-8)^2+6(-8)+k=0 \\ -512+256-48+k=0 \\ -560+256+k=0 \\ k=560-256 \\ k=304 \end{gathered}[/tex]The solution is; the value of k is 304
