Question

Rationalize the denominator of (click photo)

Answer 1

$\frac{\sqrt{-49}}{(7-2i)-(4+9i)}=\\ \frac{\sqrt{-1*7*7}}{3-11i}=\\ \frac{7i}{3-11i}*\frac{3+11i}{3+11i}=\\ \frac{(7i)*(3+11i)}{3^2-(11i)^2}=\\ \frac{21i+77i^2}{9+121}=\\ \frac{21i-77}{130}=\\ \frac{-77+21i}{130}$

so it is the last option