Answer:
k is 16
Step-by-step explanation:
Factor is ( x+2 ):
[tex]{ \sf{x + 2 = 0}} \\ { \sf{x = - 2}}[/tex]
Root is -2.
[tex]{ \bf{f(x) = 3 {x}^{3} - 4x + k}} \\ { \sf{f( - 2) = 0}} \\ { \sf{3 {( - 2)}^{3} - 4( - 2) + k = 0 }} \\ { \sf{ - 24 + 8 + k = 0}} \\ { \sf{ - 16 + k = 0}} \\ { \sf{k = 16}}[/tex]
