Answer:
x² + 4x + 1 cannot be factored
Explanation:
x² + 4x + 1 cannot be factored because the multiples of 1 (which are 1 and 1) must add to 4, which it doesn't.
An example of one that is factorisable is
x² + 6x + 9
Multiples of 9 which add to 6 are 3 and 3
(x + 3)(x + 3) or (x + 3)²