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WAEC Mathematics 2006 Question 28

Question 28

Linear and Simultaneous Equations

If x + y = 12 and 3x − y = 20, find the value of 2x − y.

  1. A.8
  2. B.10
  3. C.12
  4. D.15
Show the answer and explanation

Answer: C (12)

Explanation

Adding the equations: 4x = 32, so x = 8 and y = 4. Then 2x − y = 16 − 4 = 12.