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Problem 4 - Entrance Test

For how many integer values of b does the quadratic x² + bx + 12 have integer roots?

Correct: A

Factor pairs of 12: (±1,±12), (±2,±6), (±3,±4). Each pair gives b = -(r₁+r₂). So b = ±13, ±8, 00b17. That is 6 distinct values.