Question 322027
dividing x^3+1 by x+1 gives : 

x^3+1....|x+1
_____________ 
x^3+x^2..|x^2
_________
-x^2+1...|-x
-x^2-x...|
_________
x+1......| 1
x+1......|
_________
0

=> (x^3+1)/(x+1)=x^2-x+1