1) (2−i)3=
=8−3∙4i+3∙2i2−i3=
=8−12i−6+i=2−11i;
2) (1+i1−i)4=((1+i)2(1−i)(1+i))4=
=(1+2i+i21−i2)4=(1+2i−11+1)4=
=(2i2)4=i4=(−1)2=1.
3) (2+3i)2−(2−3i)2=
=(4+12i+9i2)−(4−12i+9i2)=
=24i.
4) (3+4i)2+(3−4i)2=
=(9+24i+16i2)+(9−24i+16i2)=
=18+32i2=18−32=−14.