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UI Post-UTME Mathematics 2018 (Model questions) Question 46

Question 46

Quadratic Equations

If 13 times a number is subtracted from the square of the number, the result is 30. Find the number

  1. A.10 or 3
  2. B.15 or −2
  3. C.6 and 5
  4. D.11 and 2
Show the answer and explanation

Answer: B (15 or −2)

Explanation

x² − 13x − 30 = 0, (x − 15)(x + 2) = 0, so x = 15 or −2.