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ISI2016-DCG-29

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The condition that ensures that the roots of the equation $x^{3}-px^{2}+qx-r=0$ are in  H.P. is

  1. $r^{2}-9pqr+q^{3}=0$
  2. $27r^{2}-9pqr+3q^{3}=0$
  3. $3r^{3}-27pqr-9q^{3}=0$
  4. $27r^{2}-9pqr+2q^{3}=0$

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