SPM 2020 Add Maths Paper 1, Question 10Progressions

Solved on video in English and Bahasa Melayu · 2 marks · Form 4, Progressions · 3:14 video

The question

Given 729, -486, 324, ..., x, 1024/81 is a geometric progression, find the value of x.

[2 marks]

Step 1

Common ratio r = -486/729 = -2/3 (check: 324/-486 = -2/3).

Why this step

Any term ÷ the term before it gives r. Checking a second pair confirms the ratio is steady, and the alternating signs tell us r is negative.

3 more steps, each with the reason for it, in the full solution

Final answer

x = −512/27

Watch every step of this question solved on video (3:14), with the reason behind each step and a box that checks your own answer.

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