Multiply and simplify the following complex numbers: (1 + 2i) x (1 - 4i)
Hi guest!
We can start off by multiplying the pairs together:
1*1=1
1*-4i=-4i
2i*1=2i
2i*-4i=\(-8i^2\). We know that i^2 = -1. So -8i^2 = -8*-1=8
Now, let's add these all together.
1-4i+2i+8 = 9-2i.
I hope this helped you!
:)
FOIL, yeilds, 1 - 4i + 2i - 8i^2 and then i^2 = -1.
1 - 4i + 2i + 8, combining like terms, 9 - 2i is the final complex number
+738 
