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UKMT Senior Kangaroo, 2025

Algebra Difficulty 3.0 AMC 10/12 Prove it United Kingdom

Part of the parabola with equation $y = ax^2 + bx + c$ is shown in the diagram. How many of the following expressions have positive values? $a$ $b$ $c$ $ab$ $bc$ $ca$ $b+c$ $abc$

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