FUNCTIONS 3

If F(x) = 4x - 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= 4x - 10

y + 10 = 4x

y + 10  = 4x

   4          4

y + 10   = x

   4

x  =   y + 10     after rearranging

           4

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

                4

Hence, F^-1(x) = x + 10     

                              4

TRY THIS………………   

If F(x) = 7x - 20; Find F^-1(x).