Solve the following equations for $z$:

(a) $iz\ =\ 4\ -\ zi$

$z\ =$ $+$ $i$,

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

$z =$ $+$ $i$,

(c) $(2\ -\ i)z\ +\ 8z^2\ =\ 0$

(This question has two solutions, one of which is $0$, find the other)

$z =$ $+$ $i$.