The graph of the system can be seen in the image at the end.
How to graph the second equation?
The second equation is a line:
y = (-1/3)*x +7/3
To graph this or any line, you only need to find two points that are solutions, then you can graph the points, and draw a line that passes trough both points.
if x = 0 we have:
y = (-1/3)*0 + 7/3 = 7/3
if x = 1
y = (-1/3)*1 + 7/3 = 6/3 = 2
So we have (0, 7/3) and (1, 2), with these two points we can graph the second line like you can see below.