Finding the geometric series of the fraction I am confused as to how to turn a fraction into a sum using geometric series.
I have $\frac{z+2}{(z-1)(z-4)}=\frac{2}{z-4}+\frac{-1}{z-1}$
I do not know how I turn the last 2 fractions into geometric series and write them as sum. Can someone please help me?

You may have previously seen that
$$\sum_{n=0}^\infty z^n =\frac{1}{1-z}, \;\;|z|<1$$
Then you may use $\frac{2}{z-4}=-\frac{2}{4}\cdot\frac{1}{1-z/4}$ and $\frac{-1}{z-1}=\frac{1}{1-z}$.
