The integer factor pairs of the first number can be written as ...
... -9 = -1×9 = -3×3 = -9×1
The sums of the factors in these factor pairs are, respectively, ...
... 8, 0, -8
The factor pair (-9, 1) meets your requirement.
A 2 over 3 because 2 and 3 both go in to 6 whereas the others don't.
