Question

If f is a function defined from R to R, is given by f(x) = 3x – 5 then f ^–1(x)  is given by __________

(a) 1/(3x-5)

(b) (x+5)/3

(c) does not exist since it is not a bijection

(d) none of the mentioned

The question was asked during an interview.

Enquiry is from Inverse of a Function in section Basic Structures: Sets, Functions, Sequences, Sums and Matrices of Discrete Mathematics

Answer 1

Correct choice is (b) (x+5)/3

Explanation: y = 3x-5, x = (y+5)/3, f ^-1(x) = (x+5)/3.