You can
put this solution on YOUR website!
(5-i)(9+6i)
Just FOIL it out, collect like terms,
then substitute -1 for iČ
and collect terms again.
FOIL it out:
45 + 30i - 9i - 6iČ
Combine the middle two terms
45 + 21i - 6iČ
Substitute -1 for iČ.
45 + 21i - 6(-1)
45 + 21i + 6
Combine like terms:
51 + 21i
Edwin