Answer:
6n+1
Explanation:
7,13,19,25 - the difference between each number is 6 so the integer before the n has to be 6. Then you can find the 0 term which will be the number that comes before the first term in this case the first is 7 so 7 minus 6 is 1 so that'll be the number that comes after the plus. You can test it works by doing 6x7(1st term) + 1 which is 43, then 6x13(2nd term) + 1 which is 79 and so on. You know it's right if the the end result is an integer. Hope this is clear