Is (x - 1) a factor of (x4 - 2x3 + x2 - x + 1)?
Factor?
Why? [Select]

here's the proof

Explanation:

x-1=0

x=1

so

f(x)=x⁴-2x³+x²-x+1

f(1)=1⁴-2.1³+1²-1+1

f(1)1-2+1-1+1

f(1)=2-2

f(1)=0

as we know When f(c)=0 then x−c is a factor of f(x)

hence x-1 is a factor of x⁴-2x³+x²-x+1