Compute the inverse transform $f$ of the given Laplace transform $F$ :

$F(s)=\frac{6s+3}{2s^2+s-1}$

$f(t)=e^{\frac{1}{2}t}+e^{-2t}$

$f(t)=\frac{1}{2}{e}^t+e^{-2t}$

$f(t)=2e^{\frac{1}{2}t}+e^{-t}$

$f(t)=e^{2t}+2e^{-t}$