Math Help - find a solution to ...

1. find a solution to ...

as a first step I say :

n>=3

r^3 - 2r^2 - r + 2 = 0

but i dont know how to continue ... can you help me?
Thank you

2. Hello, Narek!

as a first step I say: . $r^3 - 2r^2 - r + 2 \:=\: 0$
Factor: . $r^2(r-2) - (r-2) \:=\:0$

Factor: . $(r-2)(r^2-1) \:=\:0$

Factor: . $(r-2)(r-1)(r+1) \:=\:0 \quad\Rightarrow\quad r \:=\:\text{-}1,\:1,\:2$

Got it?

3. and here is my solution...

is it correct?
TNX