Find a formula for the inverse function of each of the following functions: 

a. The function that takes any input and adds 3 to it. 

b. The function that takes any input and divides it by 1/3. 

c. The function that takes any input and multiplies it by 2. 

d. The function that takes any input and raises it to 2. 

e. The function that takes any input and finds its negative reciprocal.