ECZ 2011 · O-Level Paper 1 — Variation

Given that x = 16yz2, find the values of z when x = 4 and y = 25.

  • A. z = 10 or z = -10
  • B. z = 10 only
  • C. z = 5 or z = -5
  • D. z = 100

Verified working — step 1

4 = 1625z2 gives 4z2 = 400, so z2 = 100 and z = 10 or z = …

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Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.

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