x=-1 means that any point on the line is going to have an x value of -1. Therefore the x value will never change and the line can only go up and down (it’ll be vertical)
For example, x=-1, y=0 or x=-1, y=2 or x=-1, y=4
if joined up they’ll give a vertical line which is one square to the left (-1) of the y line shown on the graph.
Similar idea for the second one, but it’s y=4 so it’ll be a horizontal line (the y coordinate never changes so it’ll go side to side).
For example, x=0, y=4 or x=2, y=4 or x=4, y=4
If joined up, they’ll show a line going across at a height of 4 squares above the x line.
the picture (if it works) should show this drawn out.
have a good day.