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JAMB Mathematics 1990 Question 17

Question 17

Algebraic Expressions

If a2 + b2 = 16 and 2ab = 7, find all the possible values of (a − b).

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

Answer: A (3, −3)

Explanation

(a − b)2 = a2 + b2 − 2ab = 16 − 7 = 9. So a − b = 3 or −3.