If (x-1) is a factor of x4+x3−2x2+x+1. Find the other factor using the factor theorem.
x3+2x2+1
Since x−1 is a factor of x4+x3−2x2+x+1, we can find the other factor by dividing x4+x3−2x2+x+1 by x−1
x3+2x2+1x−1x4+x3−2x2+x−1x4−x3 ––––––––––––––––2 2x3−2x2 2x3−2x2 –––––––––––––––––– x−1 x−1–––––– 0
∴ x4+x3−2x2+x−1 = (x−1)(x3+2x2+1)