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Find a and b if (a+b) (2 + i) = b + 1 + (10 + 2a)i - Mathematics and Statistics

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Question

Find a and b if (a+b) (2 + i) = b + 1 + (10 + 2a)i

Sum
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Solution

(a + b) (2 + i) = b + 1 + (10 + 2a)i

∴ 2(a + b) + (a + b)i = (b + 1) + (10 + 2a)i

Equating real and imaginary parts, we get

2(a + b) = b + 1

∴ 2a + b = 1  ...(i)

and a + b = 10 + 2a

–a + b = 10   ...(ii)

Subtracting (i) – subtracting (ii), we get

3a = – 9

∴ a = – 3

Substituting a = – 3 in (ii), we get

– (– 3) + b = 10

∴ b = 7  

a = – 3 and b = 7

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

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