ECZ 2021 · GCE Paper 1 — Sequences and Series
Given that 9, 15, 21, 27 ... is an Arithmetic Progression, find the formula for the nth term.
- A. 6n + 9
- B. 6n − 3
- C. 6n + 3
- D. 9n + 6
Verified working — step 1
Substitute a and d into Tn = a + (n - 1)d, then expand with care: the 6 multiplies both n and -1.The full step-by-step working and final answer, plus the video lesson for this topic, are included with Premium — checked against ECZ marking standards.
Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.
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