How do you get the domain and range of the function f(x) = absolute value of x

Also, how do you get the domain and range of the function f(x)= x to the 3rd power

How do you find the domain and range of f(x)= 1/x-4

..Instead of just listing the correct answers, please explain to me WHY they are correct, and HOW you got them (the steps). Thanks!