FUNCTIONS 1

If F(x) = 12x + 12; 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= 12x + 12

y – 12 = 12x

y – 12  = 12x

   12        12

y – 12   = x

   12

x  =   y – 12     after rearranging

            12

 y^-1 = x – 12     after interchanging x and y variables.

             12

F^-1(x) = x – 12     after interchanging x and y variables.

                12

Hence, F^-1(x) = x – 12     

                              12

TRY THIS……………………………

If F(x) = 3x + 16; Find F^-1(x).