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WAEC Mathematics 1991 (August) Question 11

Question 11

Quadratic Equations

Find the equation whose roots are −2/3 and −1/4

  1. A.12x2 + 11x + 2 = 0
  2. B.12x2 − 11x + 2 = 0
  3. C.x2 − 11/12x + 2 = 0
  4. D.12x2 − 11x − 2 = 0
  5. E.x2 11/12x − 2 = 0
Show the answer and explanation

Answer: A (12x2 + 11x + 2 = 0)

Explanation

(x + 2/3)(x + 1/4) = 0; multiply by 12: (3x + 2)(4x + 1) = 12x2 + 11x + 2 = 0.