Find the number of zeros in each of the domains.

(1) $\displaystyle z^{10} -10z^7 +2iz^4 -z^3 +i$

(a) $\displaystyle {|z|<\frac{1}{2}}$

(b) $\displaystyle {|z|<1}$

(c) $\displaystyle {|z|<2}$

(d) $\displaystyle {|z|<3}$

I have no idea how to approach these. If someone could help me out or point me in the right direction for one of these, I would appreciate it. Thanks!