Find the residue for the function: $$R(z) = \frac{6z-3}{\left(z-2i\right)\!\left(z^{2}+4\right)}$$

at $z= -2i$

$Res(-2i) =$

The "residue" is the coefficient of the $1/(z-z_0)$ term when a rational function $R(z)$ is expanded as a partial fraction, although you don't actually need to do the expansion in order to calculate the coefficient.