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WAEC Mathematics 2019 Question 27

Question 27

Algebraic Expressions

Make b the subject of the relation lb = ½(a + b)h.

  1. A.ah/(2l − h)
  2. B.(2l − h)/(al)
  3. C.al/(2l − h)
  4. D.al/(2 − h)
Show the answer and explanation

Answer: A (ah/(2l − h))

Explanation

Multiply by 2: 2lb = ah + bh. Collect b: b(2l − h) = ah, so b = ah/(2l − h).