Question 232815
If a and b are real numbers, then the product of a+bi and a-bi is 
(1) Always imaginary
(2) Always a real number
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It's 2, always a real number.
Multiply them.
(a+bi)*(a-bi) = a^2 - (bi)^2
= a^2 - (-b^2)
= a^2 + b^2
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example:
(2+3i)*(2-3i) = 4+9 = 13