Question

Having trouble getting this in (ab+i)/c form. Thanks for any help.

(2+6i)/(3-9i)

Answer 1

multiply top and bottom by \(3+9i\)

Answer 2

\[\dfrac{(2+6i)}{(3-9i)}\dfrac{(3+9i)}{(3+9i)}=\dfrac{6+18i+18i+54i^2}{3+27i-27i-81i^2}\]

Remembering \(i^2=-1\) can you now solve the problem?

Answer 3

I got -48+36i/90

so
-16+9i/30
yes? I think I multiplied by 3-9i the first time and that's why I couldn't get it to work out.