This questions is a bit confusing, but I think I know what you're saying.
A linear equation, when graphed, is always a straight line. So if you had two variables, your equation would look something like this:
y = 3x + 4
The "y" technically is another variable, but by putting the equation into this form, it does not matter anymore.
On a graph, a linear equation would begin somewhere on the y-axis and continue in a straight line in any direction from there.
Hope this helped