Which answer could be the result of two complex conjugates being multiplied together?(1 point) Responses 20 20 9−9i 9 minus 9 i 25+4i 25 plus 4 i 16i

Answer 1

When two complex conjugates are multiplied together, the result is always a real number. This is because the product can be expressed as:

\[ (a + bi)(a - bi) = a^2 + b^2 \]

This formula produces a real number \(a^2 + b^2\).

Now, let's check each of the provided options:

1. \(20\) - Real number
2. \(9 - 9i\) - Complex number
3. \(25 + 4i\) - Complex number
4. \(16i\) - Complex number

The only option that is a real number is 20. Therefore, the answer could be 20.