Z₁=1-4i z₂=-2+5i
z₁+z₂=1-4i+(-2+5i)=1-2-4i+5i=-1+i
z₁-z₂=1-4i-(-2+5i)=1-4i+2-5i=3-9i
z₁*z₂=(1-4i)(-2+5i)=1*(-2)+1*5i-4i*(-2)-4i*5i=-2+5i+8i+20=18+13i (-4i*5i i²=-1)
z₁/z₂=(1-4i)/(-2+5i)=((1-4i)(-2-5i))/((-2+5i)(-2-5i))=(-2-5i+8i-20)/(4+25)=
=(-22+3i)/29=-22/29+3i/29