ECZ 2018 · GCE Paper 1 — Index Notation
Solve the equation 22x − 1 = 16−2x.
- A. x = −16
- B. x = 110
- C. x = 12
- D. x = −110
Verified working — step 1
Write both sides with base 2: 16 = 2⁴, so 16−2x = 2−8x. Equal bases mean equal indices: 2x − 1 = −8x, so 10x = 1 and x = …The full step-by-step working and final answer 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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