Inverse Laplace Transform

I have no idea how to solve the problem with the inverse laplace transforms.

*Find the Inverse laplace transform of { 3/ (s + 4) }

I guessed that the answer, f(t) would be: 3 cos 2t


However it doesn't make sense because according to the table, -cos kt- is equal to F(s)=> s / (s^(2) + k^(2)).

In this case, s is not squared. I am not sure about k because I think it's not squared. If it is squared then k is equal to 2. That's how I got
3 cos 2t.

however if k is not squared then k is equal to 4. I am confused...

Please help:confused:

The inverse LaPlace of