Question

pleasee i need help asap with complex numbers.. compute (3i + i)/1-2i in the form of a+bi

Answer 1

\[\frac{4i}{1-2i}*\frac{1+2i}{1+2i}\]

Answer 2

\[\frac{-8+4i}{5}\]

Answer 3

how did u get that ?

Answer 4

in general multiply top and bottom by the conjugate of the bottom. the conjugate of
\[a+bi\] is \[a-bi\] and this works because
\[(a+bi)(a-bi)=a^2+b^2\] a real number

Answer 5

so in your example
\[(1+2i)(1-2i)=1^2+2^2=5\]

Answer 6

all the real work is multiplying in the numerator

Answer 7

what about the numeratorr?

Answer 8

(-8/5)+4i/5