Answer: 1, -2, -4, -7, -14, and -28.
Step-by-step explanation:
Factors of -28 are:
1 x -28 = 28
-2 x -14 = 28
-4 x -7 = 28
-7 x -4 = 28
-14 x -2 = 28
-28 x -1 = 28
