Find the next term in the following series: 6Z-25, 8A-23, 10Y-21, 128-19,

Key insight: the sequence follows three independent patterns for the first number, the letter, and the final number.

1. First numbers (before the letter): 6, 8, 10, 12, ...

2. These increase by 2 each time, so the next first number is 14.

3. Letters (middle): they alternate between two sequences: odd positions descend from Z (Z, Y, X, ...) and even positions ascend from A (A, B, C, ...).

4. Given the terms: Z (pos1), A (pos2), Y (pos3), B (pos4), the next (pos5) should be X following the descending-from-Z sequence.

5. Final numbers (after the dash): −25, −23, −21, −19, ...

6. These decrease by 2 each time, so the next final number is −17.

Note: the given fourth term appears as "128-19" in the prompt; interpreting this as "12B-19" fits the alternating-letter pattern described above.

Therefore the next term is 14X-17.