FUNCTIONS - 4

If F(x) = 10x - 6; Find F^-1(44).

Solution

HINT: F^-1(x) means inverse.

PROCEDURE:

i)1st find the inverse

ii)Then make x the subject and 

iii)then interchange x and y variables.

Let y=F(x)

So,  y= 10x - 6

y + 6 = 10x

y + 6  =   10x

   10        10

y + 6   = x

   10

x  =   y + 6      after rearranging

           10

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

             10

F^-1(x) =  x + 6      rewriting  y^-1  as F^-1(x) .

                10

F^-1(44) =  44+ 6      after interchanging x and y variables.

                   10

             = 50

                10

              = 5

Hence, F^-1(44) = 5        answer

QUIZ

1.  If  F(x) = 33x - 51; Find F^-1(-2).