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 answerC$68$
- 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'.