Given function is .

Replace with y.

Next Switch x for y and y  for x.

.

Next solve for y:

          (Multiply each side by negative one)

   (Apply distributive property: )

          (Product of two different signs is negative)

                    (Product of two same signs is positive)

     (Add 2 to each side)

      (Apply commutative property: ) \ \

              (Apply additive inverse property: )

                   (Apply additive identity property: )

               (Divide each side by 7)

                   (Cancel common terms)

                 (Simplify)

 The value of .

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

"Y " value substitute in above function,

.

The invrse of the function is .