We can solve this problem using the definition of range of function. According to the definition of domain and range of function Let f: A → B .Then, set A is called the domain of f, while set B is called the co-domain of f. The set f(A) = {f(x) : x ∈ A} is called the range of f. By using this definition we can find the range of given function. Given f (x) =
x−3
3−x
; x ≠ 3 =
−(3−x)
3−x
= - 1 ; x ≠ 3 ∴ f(x) = - 1, for all x with x ≠ 3 ∴ Range of f = {-1}