The line y=-1 is an horizontal line that passes through (0,-1).
The line x=-1 is a vertical line that passes through (-1,0).
To graph the line y=1/2x, we can find some of the points that are on it:
[tex]\begin{gathered} y=\frac{1}{2}x \\ y1=\frac{1}{2}(1) \\ y1=\frac{1}{2} \\ y2=\frac{1}{2}(2) \\ y2=1 \end{gathered}[/tex]
Two points that are on this line are (1,1/2) and (2,1).
The three lines, graphed, should look like this:
