Answer:
1, 5.1, x, 5.1x
Explanation:
5.1x can be split into 5.1 * x, therefore, we know that two of the factors are 5.1 and x. Keep in mind that 2 factors of a number are always 1 and the number itself, so we know that 1 and 5.1x are also factors. The final answer is 1, 5.1, x, 5.1x.