Q47 / 160 · TS EAMCET 2021 (04 Aug Shift 1) · Mathematics

If (a+ib)14=2+3i, then 3b-2a=

  • A
    -22
  • Correct answer
    B
    -122
  • C
    -598
  • D
    -698

Solution

Given (a+ib)14=2+3i

⇒(a+ib)=2+3i4

⇒a+ib= 2+3i22=4+9i2+12i2

=4-9+12i2

=12i-52

=144i2+25-120i

=-119-120i

Comparing with a+ib

a=-119, b=-120

Therefore 3b-2a=3(-120)-2(-119)=-122

Hence, the correct answer is option: 'B'.

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