Complex Number problem

Ixnay

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Nov 7, 2006
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2

(-6i + 2) (7+3i)



I foil it out to -42i - 18i2 +14+6i
Does a negative i squared turn out to be a positive number? because i squared is equal to -1.
If I do that it solves out to be -36i + 32 which is marked wrong.
He wrote on my paper:
-6i+14+6i
 

galactus

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Sep 28, 2005
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\(\displaystyle \L\\18+14-42\imath+6\imath\)

\(\displaystyle \L\\32-36\imath\) is the answer I get.
 

Denis

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Feb 17, 2004
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Your teacher gave answer for: -6i + 2(7 + 3i); must have been drunk :shock:
 

soroban

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Jan 28, 2005
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Ixnay said:
\(\displaystyle (-6i\,+\,2)(7\,+\,3i)\)

He wrote on my paper: -6i + 14 + 6i . . . are you sure?

Maybe your teacher is from Gamma Hydra IV
. . where the rules of math change on alternate Tuesdays.

 
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