given equations are:
[tex]\begin{gathered} x-3y=-15 \\ x=-3 \end{gathered}[/tex]
Now put the value x= -3 in another equation:
[tex]\begin{gathered} (-3)-3y=-15 \\ -3-3y=-15 \\ -3y=-15+3 \\ -3y=-12 \\ y=\frac{-12}{-3} \\ y=4 \end{gathered}[/tex]
By plotting graph for both equation:
The blue line for x-3y=-15
And red line for x=-3
