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Multiplying 2 plus 5i by its own conjugate always produces a number that is:
AEven
BReal
CZero
DOdd
Answer & Solution
Correct answer: B. Real
1. The cross terms in i cancel one another.
2. What survives has no imaginary part left.
3. The product is a real number.
_Source: OpenStax Precalculus 2e, Chapter 3, Polynomial and Rational Functions._
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