Replace with .

Interchange the variables.

Rewrite the equation as .

Multiply both sides of the equation by .

Simplify both sides of the equation.

Simplify .

Cancel the common factor of .

Cancel the common factor.

Rewrite the expression.

Cancel the common factor of .

Cancel the common factor.

Rewrite the expression.

Multiply by .

Combine and .

Add to both sides of the equation.

Replace the with to show the final answer.

Set up the composite result function.

Evaluate by substituting in the value of into .

Simplify each term.

Combine and .

Multiply by .

Divide by .

Cancel the common factor of .

Cancel the common factor.

Divide by .

Combine the opposite terms in .

Add and .

Add and .

Since , is the inverse of .

Find the Inverse Function f(x)=4/5*(x-15)