Multiple choice general knowledge math & puzzles

If one of the roots of the quadratic equation x2 + mx + 24 = 0 is 1.5, then what is the value of m?

  1. -22.5

  2. -17.5

  3. -10.5

  4. none of these
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B Correct answer
Explanation

If 1.5 is a root, substitute x = 1.5 into x² + mx + 24 = 0: (1.5)² + m(1.5) + 24 = 0, giving 2.25 + 1.5m + 24 = 0, so 1.5m = -26.25, therefore m = -26.25/1.5 = -17.5. Verification: x² - 17.5x + 24 = 0 has roots 1.5 and 16 (product = 24, sum = 17.5).

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