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AP EAMCET · Maths · Quadratic Equation

If \(\alpha, \beta, \gamma\) are the roots of \(x^3+2 x^2-3 x-1=0\) then \(\alpha^{-2}+\beta^{-2}+\gamma^{-2}=\)

  1. A 12
  2. B 13
  3. C 14
  4. D 15
Verified Solution

Answer & Solution

Correct Answer

(B) 13

Step-by-step Solution

Detailed explanation

If \(\alpha, \beta, \gamma\) are the roots of \(x^3+2 x^2-3 x-1=0\) then \(\alpha^{-2}+\beta^{-2}+\gamma^{-2}=\) \(\Rightarrow \quad \alpha+\beta+\gamma=-2 ...(i)\) \(\alpha \beta+\beta \gamma+\gamma \alpha=-3 ...(ii)\) \(\alpha \beta \gamma=1 ...(iii)\) On squaring equation…