Which answer could be the result of two complex conjugates being multiplied together?
9 - 9i
16i
20
25 + 4i
25 + 4i
The correct answer could be 25 + 4i.
The result of multiplying two complex conjugates together is always a real number. In this case, the complex conjugates are 9 + 9i and 9 - 9i.
To find the answer, we can multiply the two complex conjugates together:
(9 + 9i)(9 - 9i)
When we multiply these expressions using the distributive property, we get:
(9 * 9) + (9 * -9i) + (9i * 9) + (9i * -9i)
Simplifying this expression, we have:
81 - 81i + 81i - 81i^2
Now, if we recall that i^2 is equal to -1, we can replace i^2 with -1:
81 - 81i + 81i - 81(-1)
Simplifying further:
81 - 81i + 81i + 81
Combining like terms, we find:
162
Therefore, the answer is 162.