Answer:
39, 49, 59
Step-by-step explanation:
Note the difference between consecutive terms
9 - (- 1) = 9 + 1 = 10
19 - 9 = 10
29 - 9 = 10
The difference is a constant + 10
To obtain the next term in the sequence add 10 to the previous term
29 + 10 = 39
39 + 10 = 49
49 + 10 = 59
The next 3 terms are 39, 49, 59
