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how do i write the expression in the standard form a+b i? (9-5 i)(3 + i )

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2 Answers

 
before i start, here are some notes for "i"
 
i = √(-1)
i^2 = -1
i^3 = -√(-1)
i^4 = 1
 
foil method for ( 9-5 i) (3 + i)
 
27+9i -15i -5i^2 = 27 - 6i - 5(-1) = 27 -6i +5 = 32 -6i
 
answer is 32 -6i