x3 - 2x2 - x + 2
Let p(x) = x3 - x2 - x + 2
By trial, we find that
p(1) = (1)3 - 2(1)2 - (1) + 2
= 1 - 2 - 1 + 2 = 0
∴ By Factor Theorem, (x - 1) is a factor of p(x).
Now,
x3 - 2x2 - x + 2 = x2(x - 1) - x(x - 1) - 2(x - 1)
= (x - 1)(x2 - x - 2)
= (x - 1)(x2 - 2x + x - 2)
= (x - 1){x(x - 2) + 1(x - 2)}
= (x - 1)(x - 2)(x + 1).