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WAEC Mathematics 1999 Question 42

Question 42

Quadratic Equations

The roots of a quadratic equation in x, are −m and 2n. Find the equation.

  1. A.x2 + x(m − 2n) − 2mn = 0
  2. B.x2 − x(m − 2n) − 2mn = 0
  3. C.x2 − x(2n − m) + 2mn = 0
  4. D.x2 + x(m − 2n) + 2mn = 0.
Show the answer and explanation

Answer: A (x2 + x(m − 2n) − 2mn = 0)

Explanation

(x + m)(x − 2n) = x2 + (m − 2n)x − 2mn = 0.