To find the common difference since all the values go done, we can subtract each value.
57 - 49 = 8
49 - 41 = 8
41 - 33 = 8
33 - 25 = 8
The common difference is 8 so to find the next number, all we need to do is subtract the last number by 8.
25 - 8 = 17
Therefore, the answer is 17
Best of Luck!