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Find a and b if (a – b) + (a + b)i = a + 5i

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Question

Find a and b if (a – b) + (a + b)i = a + 5i

Sum
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Solution

(a – b) + (a + b)i = a + 5i

Equating the real and imaginary parts separately, we get,

a – b = a   ...(1)

and a + b = 5  ...(2)

From (1), – b = 0  

∴ b = 0

∴ from (2), a + 0 = 5  

∴  a = 5

Hence, a = 5, b = 0.

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Chapter 1: Complex Numbers - Exercise 1.1 [Page 6]

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