The graph will show the solution for this equation as the point(s) where the lines intersect.
The easiest points to find are the intercepts. What is x when y = 0? And what is y when x = 0
For equation 1: 3x +3(0) =12 ---> 3x=2 ---> x=4 and 3(0)+3y = 12 ---> y=4. The points are (0,4) and (4,0)
For equation 2: 0 = -x-4 --->x=-4 and y = -(0) -4 ---> y=-4. The points are (0,-4) and (-4,0)
In each case, connect the two points. You'll see the two lines are parallel. They never intersect, so this system has no solutions.