z1=4+3*i
z2=1+2*i
z12=z1+z2 
clf
hold on
plot([0,z1,z12],'-b','LineWidth',3)
plot([0,z12],'-r','LineWidth',3)
plot([z1,z12],'ob','MarkerSize',8)
hold off
grid on
axis equal
axis([0,6,0,6])
text(3.5,2.3,'z1')
text(5,4.5,'z2')
text(2.5,3.5,'z12') 
xlabel('real')
ylabel('image')