z=[(z1-1)²+1-5i]/(2+i-2i)=[(1+i)²+1-5i]/(2-i)=[1+2i-1+1-5i]/(2-i)=(1-3i)/(2-i)=(1-3i)(2+i)/(2²+1²)=(2+i-6i+3)/5=(5-5i)/5=1-i=√2[cos(-π/4)+isin(-π/4)]
