1. Complex nubmer , churchill

Hello every body
unfortunately my language is ot very good
can every body help me for understanding page 6 exercises 12 and 13 of complex variables and application of churchill that asked , establish the first of formulas (13) , sec 2
what the meaning of establish in this question ? I found this word name at dictionary but not have any mean in this part ! It mean i should prove formulas like other exercises?

thanks so much

2. Re: Complex nubmer , churchill

$\LARGE\frac{1}{{zw}} = \frac{{\overline {zw} }}{{{{\left| {zw} \right|}^2}}} = \frac{{\overline z }}{{{{\left| z \right|}^2}}}\frac{{\overline w }}{{{{\left| w \right|}^2}}} = ?$