How do you multiply (3+2i)(1-3i)(3+2i)(13i)?

1 Answer
Feb 3, 2015

Just as any other polynomial, except whenever you get i^2i2 you change it to -11

Let's go:

(3+2i)(1-3i)=3*1+3*(-3i)+2i*1-2i*3i(3+2i)(13i)=31+3(3i)+2i12i3i
=3-9i+2i-6i^2=3-7i+2i^2=39i+2i6i2=37i+2i2

The i^2i2 changes into -11 so the answer is:

3-7i+2*(-1)=3+7i-2=1+7i37i+2(1)=3+7i2=1+7i