Question

check x-2 is a factor of x^3-3x^2+2x-1

Answer 1

No (x-2) is not a factor.
If it was then x=2 would have satisfied the given polynomial as below
${x}^{3} - 3 {x}^{2} + 2x - 1 = 0$

Answer 2

x-2=0
x=2
put  value in eq 
= x^3-3x^2+2x-1
=2^3-3*2^2+2*2-1
=8-3*4+4-1
=8-12+4-1
=12-13
=-1