What does x= -4 look like on a graph as a domain and a range?

You need to learn what the words mean.

x=-4 looks like this: www.wolframalpha.com/input/?i=plot+x+%3D+-4

A function is a process that outputs a single value for each qualified input. Normally, x is considered the input and y the output. Your example either has no inputs or no outputs and is not a process, so it is not a function. Not being a function, domain and range are undefined. Domain is all qualified inputs, and range is all possible outputs. To plot that on an x-y chart gives a straight vertical line by assuming that y is an input, but in fact it indicates that there is no relation at all between x and y.