To determine whether (x + 1) is a factor of x² + x³ + x + 1, we can use synthetic division or long division to divide x² + x³ + x + 1 by x + 1.
Using synthetic division, we can write:
-1 | 1 1 0 1
| -1 0 -0
| ___________
| 1 0 0 1
Since the remainder is not zero, we can conclude that (x + 1) is not a factor of x² + x³ + x + 1.