произведение z1*z2=2*1+2*5i+i*1+5i*i=
2-5+10i+i=-3+11i
z1/z2= (2+i)(1-5i)/((1+5i)(1-5i)=(8-9i)/ 26= 8/26+9/26*i
произведение z1*z2=2*1+2*5i+i*1+5i*i=
2-5+10i+i=-3+11i
z1/z2= (2+i)(1-5i)/((1+5i)(1-5i)=(8-9i)/ 26= 8/26+9/26*i