Respuesta :
Check the picture below.
is a LINEar sequence, namely an arithmetic sequence, to which in order to get the next number we simply add a common difference to the current, in this case the common difference is 4.

Answer:
11
Step-by-step explanation:
Subtract the 3rd term to the 4th term then subtract the difference to the 3rd term to get the value of the 2nd term
19 - 15 = 4
15 - 4 = 11