FUNCTIONS 1

If F(x) = 13x + 14; 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= 14x + 10

y – 10 = 14x

y – 10  = 14x

   14        14

y – 10   = x

   14

x  =   y – 10     after rearranging

            14

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

             14

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

                14

Hence, F^-1(x) = x – 10     

                             14

TRY THIS……………………………

If F(x) = 7x + 8; Find F^-1(x).