If z = 6 + 8i, what is z times its conjugate?
Answer and explanation
Correct answer: B. 100
- Step 1: (a + bi)(a - bi) = a^2 + b^2, because i^2 = -1.
- Step 2: 6^2 + 8^2 = 100.
Answer
100.
Why not the others: The product of a complex number and its conjugate is the squared modulus, a positive real number.
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