x4 + 3x3 + 3x2 + x + 1Let p(x) = x4 + 3x3 + 3x2 + x + 1The zero of x + 1 is - 1.P(- 1) = (- 1)4 + 3(- 1)3 + 3(- 1)2 + (- 1) + 1= 1 - 3 + 3 - 1 + 1 = 1 ≠ 0∴ By factor theorem, x + 1 is not a factor of x4 + 3x3 + 3x2 + x + 1.