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JAMB Mathematics 1989 Question 17

Question 17

Indices

Solve for a positive number x such that 2(x³ − x² − 2x) = 1

  1. A.4
  2. B.3
  3. C.2
  4. D.1
Show the answer and explanation

Answer: C (2)

Explanation

2 to a power equals 1 only when the power is 0: x³ − x² − 2x = x(x − 2)(x + 1) = 0. The positive solution is x = 2.