SOLUTION: Imaginary numbers x^2-2x+12,x=1-2i

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Question 203100This question is from textbook
: Imaginary numbers

x^2-2x+12,x=1-2i This question is from textbook

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2-2x%2B12 Start with the given expression.


%281-2i%29%5E2-2%281-2i%29%2B12 Plug in x=1-2i


1-4i%2B4i%5E2-2%281-2i%29%2B12 FOIL


1-4i%2B4i%5E2-2%2B4i%2B12 Distribute


11%2B4i%5E2 Combine like terms.


11%2B4%28-1%29 Plug in i%5E2=-1


11-4 Multiply


7 Subtract


So %281-2i%29%5E2-2%281-2i%29%2B12=7


This means that x%5E2-2x%2B12=7 when x=1-2i