The equation
\(9 x^{3}-9 x^{2}+x-2=0\)
has roots \(\alpha, \beta, \gamma\).
(i) Use the substitution \(y=3 x-1\) to show that \(3 \alpha-1,3 \beta-1,3 \gamma-1\) are the roots of the equation
\(y^{3}-2 y-7=0 .\)

The sum \((3 \alpha-1)^{n}+(3 \beta-1)^{n}+(3 \gamma-1)^{n}\) is denoted by \(S_{n}\).
(ii) Find the value of \(S_{3}\).

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(iii) Find the value of \(S_{-2}\).