Solve the following equations for $z$:
(a) $iz\ =\ 4\ -\ zi$
$z\ =$

(b) $\displaystyle \frac{z}{1\ -\ z}\ =\ 1\ -\ 5i$
$z =$

(c) $(2\ -\ i)z\ +\ 8z^2\ =\ 0$
(This question has two solutions, one of which is $0$, find the other)
$z =$