We shall begin by plotting the graph of the equations given which are;
[tex]\begin{gathered} y=\frac{1}{3}x+6 \\ y=-\frac{2}{3}x+3 \end{gathered}[/tex]The black line shows the graph of y = [1/3]x + 6
The red line shows the graph of y = [-2/3]x + 3
The solution to these system of equations is at the point (-3, 5)