JRA 1. $6.6$ Solve Using the definition $z=x+i y$. $$ Z+2 \bar{z}=\frac{2-1}{1+3 i} $$ $2$ 6.7 Transform to form $z=x+i y$. $$ \left(\sqrt{3}\left(\cos \frac{2 \pi}{9}+i \sin \frac{2 \pi} {9} ight) ight]^{6} $$ 3. $6.8$ Find the complex number $z=x+y i$ $$ (-1-\sqrt{3} i)^{1 / 4} $$ CS.SD. 127