an aritmetic sequence increases by the same amount each time (if it decreases, then it increases by a negative number)
the common difference is the number that must be added to a term to get the next term
let's see if it increases by the same amount
-5 to -11 is increase of -6
-11 to -17 is increase of -6
-17 to -23 is increase of -6
-23 to -29 is increase of -6
so it appears to be aritmetic
common difference is -6
-29-6=-35
-35-6=-41
-41-6=-47
the next 3 terms are -35, -41, -47
