-8
The factors of -9 are ±1, ±3, and ±9.
If you choose -3, 3, and 1, they will add up to +1.
The factors of 21 that add up to 8 are 1 and 7.
268
-1005
167
2
The factors of 8 are 1, 2, 4, and 8. The factors that add up to 10 are 2 and 8.
Factors of 250 that add up to 8 = 1 + 2 + 5
47
212
1510
1012
15 and 4 are the factors of 120 that add up to 19.