Factor x3 + x2 + x + 1 by grouping.

To factor by grouping, you have to divide the problem into two groups:
x^3+x^2+x+1
(x^3+x^2)+(x+1)
Factor each group individually
(x^3+x^2)+(x+1)
x^2(x+1)+(x+1)
(x^2+1)(x+1)