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Express the following in the form of a + ib, a, b ∈ R, i = -1. State the values of a and b: (2 + 3i)(2 – 3i)

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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)

Sum
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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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Chapter 3: Complex Numbers - EXERCISE 3.1 [Page 37]

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