Yes, it is infinitely long - in both directions.
No, I cannot even see the x axis!
With a line graph you use lines. You put numbers at the bottom of the graph and numbers on the side. In other words the bottom numbers are on the x axis and the numbers on the side are on the y axis. Then when you have the dots on the graph you connect them and then it makes a line.
Numbers to the right of the point of origin on the x-axis are always negative.
x-axis
The horizontal axis is always your x-axis. So just put an X next to your x-axis and you've labelled it.
The horizontal axis is the real numbers.
Yes as in the same increments as numbers on the horizontal x axis.
There can be as in the x axis of the Cartesian plane.
You cannot do it as this will affect the shape of the graph. The x-axis, like the y-axis, must go in order. What is the point of them giving you values of x-axis if you can skip it?
posotive/ negative numbers
Yes, the numbers on the X-axis and the Y-axis are the scale. The scale determines the value of any given point.
Anywhere along the horizontal axis (i.e the x-axis).