SOLUTION: (3+4i)(1-2i)

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Question 244809: (3+4i)(1-2i)
Found 2 solutions by richwmiller, MathTherapy:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
(3+4i)(1-2i)
remember that i=sqrt(-1)and that i^2=-1
use foil
first term 3*1=3
outer terms 3*2i=6i
inner terms 1*4i=4i
add (6+4)(i)=10i
last terms 4i*2i=8(-1)=-8
3+10i-8
10i-5



Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
(3+4i)(1-2i)

Foil the binomials:

F ------- 3 * 1 = 3

O ------- - 2i * + 3 = - 6i

I ------- + 4i * 1 = + 4i

L ------- + 4i * - 2i = -8i%5E2 = - 8(-1) = + 8

Putting them together, we get: 3 - 6i + 4i + 8

Combining like terms gives us: highlight_green%2811+-+2i%29