Tell whether the sequence is arithmetic. if it is, what is the common difference? 19,8,-3,-14

1. find difference between numbers in sequence

Between 19 and 8: 8 - 19 = -11 (note how it is negative)
Between 8 and -3: -3 - 8 = -11
Between -3 and -14: -14 - (-3) = -11

The difference between each pair of terms are all equal to each other so the sequence is arithmetic. 

The common difference is: 11