Question

Question #b8278

Answer 1

Basically the same as we do with the real numbers. Perhaps if we rewrite this as: (3+2i)*(1-3i) then we mulitply 3 from the first paranthesis with the both constituents from the second. We do the same thing for the second constituent from the first paranthesis. While doing that, we have to be careful regarding the + and - signs just as we do with real "normal" numbers.
Please do bear in mind that once we get i^2 that it is actually (-1).

Explanation:

(3+2i)(1-3i)= 31+3(-3i)+2i1+2i(-3i)=3-9i+2i-6i^2=3-7i-6(-1)=3-7i+6=9-7i

Answer 2

`9-7i`

Explanation:

`(3+2i)(1-3i)`

`"Expand the brackets using the FOIL method"`

`=3-9i+2i-6i^2`

`[color(orange)"Reminder " i^2=(sqrt(-1))^2=-1]`

`=3-7i+6`

`=9-7i`