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WAEC Mathematics 2020 Question 14

Question 14

Algebraic Expressions

Make m the subject of the relation k = √((m − y)/(m + 1))

  1. A.m = (y + k2)/(k2 + 1)
  2. B.m = (y + k2)/(1 − k2)
  3. C.m = (y − k2)/(k2 + 1)
  4. D.m = (y − k2)/(1 − k2)
Show the answer and explanation

Answer: B (m = (y + k2)/(1 − k2))

Explanation

Square: k2(m + 1) = m − y, so k2m + k2 = m − y. Then y + k2 = m − k2m = m(1 − k2), giving m = (y + k2)/(1 − k2).