Four-function calculator with roots and powers
I am not sure it is very clear to you what your different functions are returning as you seem to be trying to print their return value even though they do not return anything special.

You do not need to change your variable names in each function without special reason. a and b are decent names in your case, you don't need to use c and d later and then e and f as there is no way to get confused anyway.

The way you use your x variable is pretty cryptic to me. I guess this is just some testing/debugging but it would help if you could submit a clean version of your code for reviewing.

Most of what happens in your function is (pretty much) the same from one to another. A good thing to do is to try to avoid repetition whenever you can and to abstract common behaviors. The quick and dirty way I've used to avoid such a repetition was to notice that you ask the user for 2 numbers anyway so it doesn't really matter which operator we will use them for. My minimalist solution stores things in a dictionary (you could improve the content of the dictionary if you wanted to have more things changing from one operator to another such as user prompts).

#!/usr/bin/python
import operator

operations={
        'a':('Addition',      operator.add),
        's':('Substraction',  operator.sub),
        'm':('Multiplication',operator.mul),
        'd':('Division',      operator.truediv),
        'p':('Power',         operator.pow),
        'r':('Root',          lambda x, y:x**(1/y)),
}

while True:
        # TODO : Next line could be generated from the list if it keeps growing
        x = input('(Add, Subtract, Divide, Multiply, Powers, Roots or Quit)').lower()
        if x in operations:
                operation_name,operator=operations[x]
                print(operation_name)
                a = float(input('First Number:'))
                b = float(input('Second Number:'))
                print("Your answer is ",operator(a,b))
        elif x.startswith('q'):
                break
        else:
                print("Please type the first letter of what you want to do.")