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AP EAMCET · Maths · Complex Number

If a complex number z is such that (7+i)(z+z¯)-(4+i)(z-z¯)+116i=0, then zz¯=

  1. A 400
  2. B 300
  3. C 200
  4. D 100
Verified Solution

Answer & Solution

Correct Answer

(C) 200

Step-by-step Solution

Detailed explanation

Consider a complex equation, z=x+i y Its conjugate is z¯=x-iy Now,(7+i)(z+z¯)-(4+i)(z-z¯)+116i=0 ⇒(7+i)(2x)-(8iy-2y)+116i=0 ⇒(14x+2y)+i(2x-8y+116)=0 The equations obtained are ⇒2x-8y+116=0 ⇒14x+2y=0 From the above two equations,…