there are 6: 21,28,35,42,49,56
20, 40, 60, 80, 100 and so on.
-1540
They are: 20, 40, 60, 80, 100 and 120
(20) and (negative 3)
60, 120, 180 and so on.
There are many possible answers. One such of the following: {3, 20, and 34 lots of -1}. Another is {-15, 4}
28, 35, 42, 49, 56.
Multiplies by 3, then subtracts 7
There are infinitely many possible answers. Among these are: 6*7, 60*0.7, 600*.007, 84*1/2, 840*1/20
Nine of them are evenly divisible by 5, if you include 20 and 60.
20 there are 3 feet to a yrd 60 divided by 3 equals 20
-56