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JAMB Mathematics 1979 Question 29

Question 29

Linear and Simultaneous Equations

Solve the simultaneous linear equations:
2x + 5y = 11
7x + 4y = 2

  1. A.x = −8, y = 1
  2. B.x = −2, y = 4
  3. C.x = 2, y = −3
  4. D.x = −34/27, y = 73/27
  5. E.x = 346/189, y = −73/27.
Show the answer and explanation

Answer: D (x = −34/27, y = 73/27)

Explanation

Multiply the first by 4 and the second by 5 and subtract: 27x = −34, so x = −34/27. Then 5y = 11 + 68/27 = 365/27, so y = 73/27.