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GCE Mathematics 1989 Question 45

Question 45

Quadratic Equations

Solve for x: (x2 + 2x + 1) = 25

  1. A.−6, −4
  2. B.6, −4
  3. C.6, 4
  4. D.−6, 4
  5. E.5, 5
Show the answer and explanation

Answer: D (−6, 4)

Explanation

x2 + 2x + 1 = (x + 1)2 = 25, so x + 1 = ±5, giving x = 4 or x = −6.