Question

O quociente de 5i por 3-4i será :
A) -4/5+3/5i
B) -1/5-i
C) 1+2i
D) 0
E) 1/3i

Answer 1

$\frac{5i}{3-4i}.\frac{3+4i}{3+4i}=\frac{5i(3+4i)}{9+16} =\frac{-20+15i}{25}=-\frac{4}{5}+\frac{3}{5}i$