Explanation:
I cannot draw here, but it is easily explained.
x = -1
means the line that represents all points with the x-coordinate of -1.
so, e.g.
...
(-1, 8)
(-1, 5)
(-1, 1)
(-1, 0)
(-1, -2)
(-1, -6)
...
you see the pattern ? it is all these points and all infinitely many others with (-1, y), with y being any real number you can think of.
so, it is the vertical line (parallel to the y-axis) that goes through x = -1 on the x-axis.