The roots of the equation $x^3-3x-2=0$  are

clearly -1 is a root of the given equation and -1 is also root of 

$$\begin{gathered} f^{\text{'}}\left(x\right)=3x^2-3=0 , hence -1 is common root of the equations \\ f\left(x\right)=0 and f^{\text{'}}\left(x\right)=0 . \\ \therefore -1 is the repeated root. \\ \sin ce S_1=0\Rightarrow third root =2 \end{gathered}$$

roots are -1,-1,2