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Question
Express the following in the form of a + ib, a, b∈R i = `sqrt(−1)`. State the values of a and b:
(2 + 3i)(2 – 3i)
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Solution
(2 + 3i)(2 – 3i) = 4 – 9i2
= 4 – 9(– 1) ...[∵ i2 = – 1]
= 4 + 9
= 13
∴ (2 + 3i)(2 – 3i) = 13 + 0i
∴ a = 13 and b = 0
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