-21 and -1
84
41
The factor pairs of 21 are (21, 1) (7, 3) Even considering their negative counterparts, they don't add up to -13.
They are 21 and 28
41
The multiples of seven between 20 and 60 are: 21, 28, 35, 42, 49, 56.
21
-20
-21
21, 35, 49, 63, 77.
4, 8, 12, 16, 20.