I'm have a few questions about i:
-How come sometimes you solve to get rid of it, other times you leave the it? For example, 4(-2+3i) becomes -8+12i, while other times (3+2i)(3-2i) yields 13 (the i is turned into negative one). How do you know when to keep the i and when not to?
-How come in (3+2i)(3-2i) The answer, 9+-4i^2 becomes 9 + 4. But I don't get it. I would have thought -4 times i would be 4, then times i again would be -4. Why?
i^2=-1
memorize that.
Now on the first one, i is not -1
(3+2i)(3-2i)=9-4i^2=9-4(-1)=13
it is the i2 that is -1