Remember the following rule for adding up two complex numbers:
[tex](a+bi)+(c+di)=(a+c)+(b+d)i[/tex]
The real parts of both numbers add up, the same applies for the imaginary parts.
Then:
[tex]\begin{gathered} (6+4i)+(3-3i)=(6+3)+(4-3)i \\ \\ \therefore(6+4i)+(3-3i)=9+i \end{gathered}[/tex]
Therefore, the correct choice is option B) 9+i.
