Mathematics for IGCSE & O level - Sequences (Section 3 - No. 18)
Given the sequence: 4, 1, -2, -5, ... what is the nth term?
-3n + 7
3n-7
3n+7
-3n-7
Giải thích
The sequence decreases by 3 each term, and when n = 1, the term is 4. The formula is -3n+7.