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WAEC Mathematics 2010 Question 29

Question 29

Algebraic Expressions

If y = 2√(x2 + m)/3N, make x the subject of the formula.

  1. A.√(9y2N2 − 2m)/2
  2. B.√(9y2N2 + 2m)/2
  3. C.√(9y2N2 − 4m)/2
  4. D.√(9y2N2 + 4m)/2
Show the answer and explanation

Answer: C (√(9y2N2 − 4m)/2)

Explanation

3Ny = 2√(x2 + m). Square: 9N2y2 = 4x2 + 4m, so x2 = (9y2N2 − 4m)/4 and x = √(9y2N2 − 4m)/2.