Setting the domain and range of a line

I am doing a math project when I am drawing with conics (and lines as well) to make a picture.

I have a question about setting the domain and range of a line segment.

Since the domain and range of a line are generally infinite, I cannot use that for my project, so I must specify an equation for the line I am drawing along with a domain and range to cut off part of that line so only what I want is left.

If I want a line that goes from points (-7, -14) to (-4, 14) what would be the domain and range of that line?

I know the equation would be y = -14 but I'm not sure about setting the domain and range for that.

Sorry if it's a simple problem!

Also please tell me WHY so I can do it for the rest of my problems.

THANKS! (Rofl)