z₁+z₂=7-i+1+6i=8+5i
z₁*z₂=(7-i)(1+6i)=7+42i-i-6i²=7+41i-6*(-1)=7+41i+6=13+41i (i²=-1)
z₁ / z₂= 7-i (7-i)(1-6i) 7-42i-i+6i² 7-43i+6(-1) 1-43i 1-43i
= --------- = ----------------- = ----------------- =------------------ =----------- =------------=
1+6i (1+6i)(1-6i) 1-(6i)² 1-36i² 1+36 37
1 43
= ------ - -------- *i
37 37