Multiply x2 + x + 1 by x2 – x + 1
- x4 - x + x2
- x4 - x2 + x2
-
x4 + x2 + 1
- x4 + x2
The correct answer is: C
Explanation
(x2 + x + 1)( x2 - x + 1)= x2(x2 + x + 1) - x(x2 + x + 1) + (x3 + x + 1)
= x4 - x3 + x2 + x3 - x2 - x + 1
= x4 + x2 + 1