Answer:
15: 1 3 5 15
20: 1 2 4 5 10 20
Explanation:
This assumes you are only factoring the coefficients of the expression. Using this assumption, we simply create a list of factors of the coefficients.
15 -> 1 * 15, 3 * 5 --> 1 3 5 15
20 -> 1 * 20, 2 * 10, 4 * 5 --> 1 2 4 5 10 20
If you don't assume factoring of just the coefficients, then 20x factors
20x: 1 2 4 5 10 20 x
Cheers.