Question 3287
I'm not certain about this. If you are asking for the nth number in the sequence 25, 52, 79 ..., consider the difference between to consecutive numbers in the sequence. The difference between 79 and 52 is 27, likewise, the difference between 79 and 52 is 27. This suggests that the equation will have the form 27n + c, where c is some constant. Now consider the first value 25. The equation tells us that  {{{27(1) + c = 25}}}, so the c must equal -2. Therefore, the nth number in the sequence is {{{27*n - 2}}}. This is close to what you've got, {{{26n - 2 - n}}}, if you had {{{26n - 2 + n}}}, then our analyses would agree.<br>
For x, I would follow the same technique. The sequence we have is 3, 7, 11,... which means the difference between consecutive numbers is 4. This means the nth number is {{{4n + c}}}. To find this constant, look at the first value. {{{4*(1) + c = 3}}} means the constant must be -1, so our equation is 4n - 1. Interestingly, this is the same as your solution after a little algebra.<br>
I'm not sure why you want to combine them.

Does this make sense?