Given the function f(x) = 3x, find the value of f^-1(81)

Solution:

A function is a process or a relation that associates each element 'a' of a non-empty set A , at least to a single element 'b' of another non-empty set B.

A relation f from a set A (the domain of the function) to another set B (the co-domain of the function) is called a function in math. 

y = f(x) = 3x

x = y/3

Interchanging x and y

y = x/3

f^-1(x) = x/3

f^-1(81) = 81/3 = 27

Given the function f(x) = 3x, find the value of f^-1(81)

Summary:

Given the function f(x) = 3x, the value of f^-1(81) is 27