FUNCTIONS F2

 

If F(x) = 2x + 60; Find F^-1(x).

 

Solution

 

HINT: F^-1(x) means inverse.

 

PROCEDURE:

Make x the subject and then interchange x and y variables.

 

Let y=F(x)

 

So,  y= 2x + 60

 

y – 60 = 2x

 

y – 60  = 2x

   2          2

 

y – 60   = x

   2

 

x  =   y – 60     after rearranging

           2

 

 y^-1 = x – 60     after interchanging x and y variables.

             2

 

F^-1(x) = x – 60     after interchanging x and y variables.

                2

 

Hence, F^-1(x) = x – 60     

                             2

 

TRY THIS……………………………

 

If F(x) = 4x - 26; Find F^-1(x).