Chapter 4.3, Problem 1E

For the function

$f(x)=x^{\text{4}}-\text{6}{x}^{\text{3}}+x^{\text{2}}+\text{24}x-\text{2}0,$

use long division to determine whether each of the following is a factor of f(x).

1. a) x + 1
2. b) x − 2
3. c) x + 5