WAEC Further Mathematics 2020 Question 6

Question 6

Functions

Given that x: R → R is defined by x = (y + 1)/(5 − y), y ∈ R, find the domain of x.

  1. A.{y : y ∈ R, y ≠ 0}
  2. B.{y : y ∈ R, y ≠ 1}
  3. C.{y : y ∈ R, y ≠ 5}
  4. D.{y : y ∈ R, y ≠ 7}
Show the answer and explanation

Answer: C ({y : y ∈ R, y ≠ 5})

Explanation

The expression is undefined only when 5 − y = 0, so y ≠ 5.