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what is (-x+9i) (x-9i)

 Mar 14, 2017
 #1
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+5

(-x+9i) (x-9i)  =

 

-x^2 + 9i *x  + 9i * x - 81i^2

 

-x^2 + (18i)x - 81 (-1)   =

 

-x^2 + (18i)x + 81

 

 

cool cool cool

 Mar 14, 2017

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