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AP EAMCET · Maths · Determinants

If \(\alpha, \beta, \gamma\) are the roots of \(\left|\begin{array}{ccc}1-x & -2 & 1 \\ -2 & 4-x & -2 \\ 1 & -2 & 1-x\end{array}\right|=0\), then \(\alpha \beta+\beta \gamma+\gamma \alpha=\)

  1. A \(6\)
  2. B \(8\)
  3. C \(0\)
  4. D \(-4\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(0\)

Step-by-step Solution

Detailed explanation

\(\left|\begin{array}{ccc}1-x & -2 & 1 \\ -2 & 4-x & -2 \\ 1 & -2 & 1-x\end{array}\right|=0\) \(\begin{aligned} & \Rightarrow(1-x)\{(4-x)(1-x)-4\}+2\{-2(1-x)+2\}+ \\ & 1(4-4+x)=0 \Rightarrow x^3-6 x^2=0 \end{aligned}\) \(\because \alpha, \beta\) and \(\gamma\) are the roots of…
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