In general, to graph a line, draw two points of it on the plane and cross them using a straight line.
Finding two points on each line,
[tex]\begin{gathered} x-y=-1 \\ x=0\Rightarrow y=1 \\ \Rightarrow(0,1) \\ x=1\Rightarrow y=2 \\ \Rightarrow(1,2) \end{gathered}[/tex]
And
[tex]\begin{gathered} x-3y=-9 \\ x=0\Rightarrow y=3 \\ \Rightarrow(0,3) \\ x=3\Rightarrow y=4 \\ \Rightarrow(3,4) \end{gathered}[/tex]
Graphing both lines on the plane
The intersection point is the solution to the system. The answer is (x,y)=(3,4)
