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AP EAMCET202119 Aug 2021Morning ShiftMathematicsSequences and SeriesActual

Let f ( x ) = x 3 + a x 2 + b x + c be polynomial with integer coefficients. If the roots of f ( x ) are integer and are in Arithmetic Progression, then ' a ' cannot take the value

Options

  1. A− 642
  2. B1214
  3. C1323
  4. D1626

Correct answer

B. 1214

Step-by-step solution

Given that, f ( x ) = x 3 + a x 2 + b x + c Now, since the roots of the polynomial are in Arithmetic Progression, Let the roots are s - t ,   s ,   s + t ⇒ s - t + s + s + t = - a 1 ⇒ - 3 s = a Hence, a must be multiple of 3 . From given options we see that only 1214 is not multiple of 3 .

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