Q57 / 160 · TS EAMCET 2023 (14 May Shift 1) · Mathematics

$\alpha, \beta, \gamma$ are the roots of the equation $x^3+2 x^2-x-2=0$ then $\alpha^6+\beta^6+\gamma^6=$

  • A
    $3$
  • B
    $129$
  • Correct answer
    C
    $68$
  • D
    $192$

Solution

$\alpha+\beta+\gamma=-2 ; \alpha \beta+\beta \gamma+\gamma \alpha=-1 ; \alpha \beta \gamma=2$ $\begin{aligned} & x^3+2 x^2-x-2=0 \\ & \Rightarrow(x+1)(x-1)(x+2)=0 \\ & \therefore x=1,-1,-2 \\ & \alpha^6+\beta^6+\gamma^6=(1)^6+(-1)^6+(-2)^6=66\end{aligned}$

Hence, the correct answer is option: 'C'.

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