z₁=2+3i, z₂=1-2i
z₁+z₂=2+3i+1-2i=3+i
z₁-z₂=2+3i-(1-2i)=2+3i-1+2i=5i+1
z₁*z₂=(2+3i)(1-2i)=2-4i+3i-6i²=2-i-6*(i²)=2-i+6=8-i
z₁/z₂=(2+3i)/(1-2i)=(2+3i)(1+2i)/(1-2i)(1+2i)=(2+2i+3i+6i²)/(1-(2i)²)=(2+5i-6)/(1+4)=(5i-4)/5
z₁=2+3i, z₂=1-2i
z₁+z₂=2+3i+1-2i=3+i
z₁-z₂=2+3i-(1-2i)=2+3i-1+2i=5i+1
z₁*z₂=(2+3i)(1-2i)=2-4i+3i-6i²=2-i-6*(i²)=2-i+6=8-i
z₁/z₂=(2+3i)/(1-2i)=(2+3i)(1+2i)/(1-2i)(1+2i)=(2+2i+3i+6i²)/(1-(2i)²)=(2+5i-6)/(1+4)=(5i-4)/5