What is the value of the product (3 – 2i)(3 + 2i)? A. 5 B. 9 + 4i C. 9 – 4i D. 13
2 answers:
Answer:
D. 13
Step-by-step explanation:
You can do the product in the straight-forward way ...
... (3 -2i)(3 +2i) = 3·3 +3·2i -3i·3 -(2i)(2i)
... = 9 +6i -6i -4i² . . . . . note the middle two terms cancel
Recognize that i = √-1, so i² = -1. Then the sum is
... = 9 -4(-1) = 9+4 = 13
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Your graphing calculator can do this product, too.
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