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WAEC Further Mathematics 2024 Objective — Question 3

Question 3 of 40 from the West African Examinations Council (WAEC) Further Mathematics 2024 Objective paper, with the correct answer and a full explanation.

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3. If sqrt(x) - 6/sqrt(x) = 1, find the value of x.

  • A. 9Correct
  • B. 16
  • C. 25
  • D. 36

Explanation

Multiplying through by sqrt(x): (sqrt(x))^2 - sqrt(x) - 6 = 0. Let sqrt(x)=u: u^2-u-6=0 => (u-3)(u+2)=0 => u=3 or u=-2. Since sqrt(x) cannot be negative, sqrt(x)=3, so x=9 (x=4 from u=-2 is extraneous and does not satisfy the original equation).

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