2X^3-3X+1 =2X^3-2-3X+1+2 =2(X^3-1)-3X+3 =2(X^3-1)-3(X-1) =2(X-1)(X^2+X+1)-3(X-1) =(X-1)(2(X^2+X+1)-3) =(X-1)(2X^2+2X+2-3) =(X-1)(2X^2+2X-1)
