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: