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JAMB Mathematics 1983 Question 15

Question 15

Algebraic Expressions

Simplify (x − 7)/(x2 − 9) × (x2 − 3x)/(x2 − 49)

  1. A.x/((x − 3)(x + 7))
  2. B.(x + 3)(x + 7)/x
  3. C.x/((x − 3)(x − 7))
  4. D.x/((x + 3)(x + 7))
  5. E.x/((x + 4)(x − 7))
Show the answer and explanation

Answer: D (x/((x + 3)(x + 7)))

Explanation

Factorise: (x − 7)/((x − 3)(x + 3)) × x(x − 3)/((x − 7)(x + 7)). Cancelling (x − 7) and (x − 3) leaves x/((x + 3)(x + 7)).