z1+z2=8+3i
z1-z2=2-9i
z1*z2=15+30i-9i-18i^2=33+21i
z1/z2=(5-3i)(3-6i)/(3+6i)(3-6i)=(15-30i-9i-18)/9+36=-3-39i/45=-1/15 -13i/15
z1+z2=8+3i
z1-z2=2-9i
z1*z2=15+30i-9i-18i^2=33+21i
z1/z2=(5-3i)(3-6i)/(3+6i)(3-6i)=(15-30i-9i-18)/9+36=-3-39i/45=-1/15 -13i/15