Question 1063158
{{{z=sqrt(21-20i)=x+yi}}}
So,
{{{x^2-y^2=21}}}
{{{2xy=-20}}}
and
{{{z^2=x^2+y^2=sqrt(21^2+20^2)=29}}}
So then,
{{{x^2-y^2+x^2+y^2=21+29}}}
{{{2x^2=50}}}
{{{x^2=25}}}
{{{x=0 +- 5}}}
and
{{{2(5)y=-20}}}
{{{y=0 +- 2}}}
So the solution is,
{{{z=5-2i}}} or {{{z=-5+2i}}}
{{{z=0 +- (5-i)}}}