Question

Simplify the following radical: (6+4i)(1+3i)

Answer 1

start by expanding the factors, and then simplify like terms. keep in mind the rule
\(i^2=-1\)

Answer 2

do FOIL then combine like terms in a+bi

Answer 3

here is my two cents
you can "foil" (ugh) if you like, but the way to multiply two complex numbers is
\[(a+bi)(c+di)=(ac-bd)+(ad+bc)i\]

Answer 4

So, 6+18i+(-12)+(-12)?

Answer 5

no

Answer 6

6×1
6×3i
4i×1
4i×3i

Answer 7

\[i ^{2}=-1\]

Answer 8

Call me stubborn, but is it something like 6-(-12)+(-22)?

Answer 9

you got the 6 right

Answer 10

Alright, here is what I have written down.

Answer 11

(6*1-12i)+(18i+4i)i

Answer 12

I have a feeling that when I multiplied I shouldn't have switched the 12 to a negative.

Answer 13

Nor the others.

Answer 14

Do 6×1
6×3i
4i×1
4i×3i

Answer 15

after that ill help combine like terms

Answer 16

I did, and for those I got the following.
6
18i
4i
-12

Answer 17

okay now combine like terms in A+bi form
6-12
18i+4i

Answer 18

-6+22i?

Answer 19

yes

Answer 20

That is as low as it can go I assume?

Answer 21

yes

Answer 22

Alright I have a few more questions if you wouldn't mind sticking around.

Answer 23

I can try to help

Answer 24

(2-5i)(7+i)?

Answer 25

use foil for this one too
2×7
2×i
-5i×7
-5i×i

Answer 26

14
2i
-35i
5?

Answer 27

yes now combing like terms in a+bi form
14+5
2+(-35i)

Answer 28

19-33i?

Answer 29

yes

Answer 30

Thank you! Now, one last one. (-3-6i)(4-2i)

Answer 31

-3×4
-3×-2i
-6i×4
-6i×-2i
remember 2 negatives will make a positive

Answer 32

So:
-12
6i
-24i
12?

Answer 33

wouldnt be 12 remember multiplying those will make it positive the i^2=-1 so you multiply negative by positive

Answer 34

So -12?

Answer 35

yes -12-12
6i-24i

Answer 36

Danke sehr!

Answer 37

And one factoring question: 5x^2-30x=0

Answer 38

ewww factoring lol

Answer 39

umm hold on ill look at it

Answer 40

Heh.

Answer 41

http://www.algebrahelp.com/calculators/equation/calc.do?equation=5x%5E2-30x%3D0&solvf=AUTO

Answer 42

This...will prove VERY USEFUL.

Answer 43

Danke und auf wiedersehen!