-16
The factor pairs of 36 are (36, 1) (18, 2) (12, 3) (9, 4) (6, 6) None of them add up to 9. If that was -36, you could use 12 and -3
23
-12 and +5
19
-40
-27
164
-36
144
No integers. It works the other way around. 6 and 2 multiply to 12, add to 8.
-13