Answers

2016-06-25T19:48:48+08:00
Yes, 3,7,11,15,19 is an arithmetic sequence. they have a common difference which is 4. 

3+4= 7
7+4= 11
11+4= 15
15+4= 19


0
why 4..?
to get the common difference you have to subtract 2nd term to the 1st term, 3rd term to second term and so on .