Answer:
[tex]\displaystyle \frac{7}{3-15i}=\frac{7}{78}+\frac{35}{78}i[/tex]
Step-by-step explanation:
[tex]\displaystyle \frac{7}{3-15i}\\\\\frac{7}{3-15i}*\frac{3+15i}{3+15i}\\\\\frac{21+105i}{9-225i^2}\\\\\frac{21+105i}{9+225}\\\\\frac{21+105i}{234}\\\\\frac{21}{234}+\frac{105}{234}i\\ \\\frac{7}{78}+\frac{35}{78}i[/tex]
