show that :

$\displaystyle |(2\overline{z}+5)(\sqrt{2}-i)|=\sqrt{3}|2z+5|$

so for I have:

$\displaystyle = |(2\overline{z}+5)|\times |(\sqrt{2}-i)|$

$\displaystyle = |(2z+5)| \times |(\overline{\sqrt{2}+i})|$

now what I don't understand is how $\displaystyle {\color{blue} |(\overline{\sqrt{2}-i})| = |(\overline{\sqrt{2+1}})|} = |\sqrt{3}| = \sqrt{3}$