FUNCTIONS 4

If F(x) = 13x + 10; 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= 13x + 10

y – 10 = 13x

y – 10  = 13x

   13        13

y – 10   = x

   13

x  =   y – 10     after rearranging

            13

 y = x – 10     after interchanging x and y variables.

             13

F^-1(x) = x – 10     after interchanging x and y variables.

                13

Hence, F^-1(x) = x – 10     

                             13