a) First, write the equation as

Interchange the x and y.

Solve for y.

The inverse is also a linear function.

b) Follow same procedure as (a) above.

This inverse is not a function because any acceptable value of domain x yields two values for range y.

c) Follow same procedure as (a) above.

This inverse is not a fraction because any acceptable value of domain r yields 2 values for range y.