Question

Using Factor theorem show that (x-1) is a factor of x^20 -1

Answer 1

If x-1 is a factor of
${x}^{20} - 1$
then
f(1)=0
So put x=1 in equation
${x}^{20} - 1 \\ = {1}^{20} - 1 \\ = 1 - 1 \\ = 0$
Hence x-1 is a factor