The function is .

Replace with y.

Next switch x for y and y  for x.

.

Next solve for y :

       (Multiply each side by 6)

    (Apply distributive property: )

              (Cancel common terms)

                       (Multiply: )

          (Subtract 6 from each side)

                (Apply additive inverse property: )

                      (Apply additive identity property: )

        (Multiply each side by negative one)

(Apply distributive property: )

                   (Product of two same signs is positive)

                       (Product of two different signs is negative)

The value of .

Write in function notation, using to represent the inverse of the function f.

"y" value substitute in above function,

.

The inverse function of is  .