I am having trouble with the following questions.

1) Find $\displaystyle z^6\div w^4$ for $\displaystyle z=-1+\sqrt{3i} and w=1+i$

2) solve over C, $\displaystyle z^2=8+15i$

3) Express $\displaystyle 2\sqrt{3}+2i\div1-3i$ in polar form

4) find all solutions of the equation $\displaystyle z^3-(\sqrt{5}-i)z^2+4z-4\sqrt{5}+4i=0$

5) Express $\displaystyle 1+\sqrt{3i} in polar form$