If \( \alpha=1 \) and \( \beta=1+i\sqrt{2} \), where \( i=\sqrt{-1} \) are two roots of the equation \( x^3+ax^2+bx+c=0,\, a,b,c \in \mathbb{R} \), then is equal to:
\( -2 \)
\( -4 \)
\( -8 \)
\( -10 \)