FUNCTIONS-1

If F(x) = 2x + 6; 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 + 6

y – 6 = 2x

y – 6  = 2x

  2        2

y – 6   = x

   2

x  =   y – 6     after rearranging

            2

 y^-1 = x – 6     after interchanging x and y variables.

            2

F^-1(x) = x – 6     after interchanging x and y variables.

               2

Hence, F^-1(x) = x – 6     

                            2

TRY THIS……………………………

If F(x) = 3x + 10; Find F^-1(x).