Answer:
n + 4
Explanation:
For this problem, we must simply determine the operation that is occurring between each input and each output.
Let's start with the first input, 1, and the first output, 5. Notice 5-1 = 4. Let's assume that this difference holds. We need to check the next option.
The second input, 5, and the second output, 9. Notice 9-5 = 4. It would seem that our assumption holds. Let's check the next case to ensure the validity of our assumption.
The third input, 7, and the third output, 11. Notice 11 - 7 = 4. Since all three cases match our assumption, we will apply our assumption to the generalized input, n.
When the input is n, our output will be n + 4, as we have determined with our assumption from the previous inputs and outputs that we analyzed.
Thus, when input in n, output is n+4.
Cheers.