ECZ 2025 · O-Level Paper 1 — Quadratic Functions

The following is the graph of y = -x² + 12x - 11. The graph cuts the x-axis at A and B. Find the maximum value of y.

Verified working — step 1

The maximum sits at the turning point, and completing the square rewrites the curve so that point can be read directly.

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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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