Respuesta :

Answer:9

Step-by-step explanation: 4+9=13, 13+9=22, 22+9=31, 31+9=40, 40+9=49.

As you can see, 9 is being added so the answer is 9

Answer:

a(n+1) = a(n) + 9

Step-by-step explanation:

The terms just before and just after each are 9 more than the previous term or 9 less than the previous term.  In other words, the common difference is 9.

Thus, the recursive formula is a(n+1) = a(n) + 9