Question 10
Fractions, Decimals and ApproximationWhat is the value of (2 + 3i)(2 − 3i), where i is the imaginary unit?
- A.13
- B.−13
- C.5
- D.−5
Show the answer and explanation
Answer: A (13)
Explanation
(2 + 3i)(2 − 3i) = 4 − 9i2 = 4 + 9 = 13, since i2 = −1.