1
i^40-t^21=(i²)^20-i*(i²)^10=(-1)^20-i*(-1)^10=1-i
2
x²-6x+34
D=36-136=-100
√D=10i
x1=(6-10i)/2=3-5i U x2=3+5i
3
1)z1=5+4i;z2=3+2i
z1+z2=5+4i+3+2i=8+6i
z1-z2=5+4i-3-2i=2+2i
z1*z2=15+12i+10i+8i²=15+22i-8=7+22i
z1/z2=(5+4i)(3-2i)/[(3+2i)(3-2i)=(15-10i+12i-8i²)/(9-4i²)=(15+2i+8)/(9+4)=
=(23+2i)/13=23/13+2/13*i
2)z1=2-i;z2=3i
z1+z2=2-i+3i=2+2i
z1-z2=2-i-3i=2-4i
z1*z2=6i-3i²=6i+3
z1/z2=(2-i)*(-i)/(-3i²)=(-2i+i²)/3=(-2i+1)/3=-2/3*i+1/3
4
1)(1-2i)²=1-4i+4i²=1-4i-4=-3-4i
2)(3+2i)²=9+12i+4i²=9+12i-4=5+12i