Complex Number problem

[Ixnay]

(-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]

\(\displaystyle \L\\18+14-42\imath+6\imath\)

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

 

[Denis]

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

 

[soroban]

\(\displaystyle (-6i\,+\,2)(7\,+\,3i)\)

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.