A simple answer, based on a linear rule is
U(n) = 5n - 23 for n = 1, 2, 3, ...
It is: 5n+3 and so the next term is 28
The nth term is 7n-3 and so the next term will be 39
It is: 25-7n
7n - 3
Un = 25 - 7n
Un = 5n - 2
It is: 5n+3 and so the next term is 28
The nth term is 18 -3n and so the next term will be 3
I suspect that the first term should be "negative 3", ie the sequence is -3, 1, 5, 9, 13, 17, ... The nth term is 4n - 7
The nth term is: n^2 +2 and so the next number will be 38
The nth term is 7n-3 and so the next term will be 39
The next term is 45 because the numbers are increasing by increments of 3 5 7 9 and then 11
7n - 3
It is: 25-7n
The nth term is 4n - 3
It is: 10n-7 and so the next term is 43
Un = 25 - 7n