Multiplies to -1120 adds to 3

With these, always write out the multiples first.

Start like this:
(assume one of the factors is negative)
1 and 1120
2 and 560
4 and 280
5 and 224
7 and 160
8 and 140
10 and 112
14 and 80
16 and 70
20 and 56
28 and 40
32 and 35

from those, the obvious choice is the one with a difference of three. In this case, 32 and 35, because -32 + 35 equals 3.