Question 255196
7+3i/3+9i

Multiply numerator by the complex conjugate of 3+9i.

The complex conjugate of 3+9i is 3-9i

So we have:

[(7+3i)*(3-9i)]/[3+9i)*(3-9i)] = 

[21-63i+9i+27i^2]/[9-81i^2]  =
[21-54i+(27*-1)]/[9-81*(-1)] =
(21-27-54i)/(9+81) =
(-6-54i)/90 = -1/15 - 3i/5 = = (-1/5)*(1/3 + 3i)