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WAEC Mathematics 2022 Question 13

Question 13

Linear and Simultaneous Equations

If 5x + 3y = 4 and 5x − 3y = 2, what is the value of (25x2 − 9y2)?

  1. A.20
  2. B.16
  3. C.2
  4. D.8
Show the answer and explanation

Answer: D (8)

Explanation

25x2 − 9y2 = (5x + 3y)(5x − 3y) = 4 × 2 = 8.