Question 890643
Both of these equations are for straight lines.  Any equation of the form ax + by = c (standard form) or y=mx+b (slope intercept form) is an equation of a straight line.  To graph a line, find two points.  Connect them.  <P>
The graph will show the solution for this equation as the point(s) where the lines intersect.<P>
The easiest points to find are the intercepts.  What is x when y = 0?  And what is y when x = 0<P>
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)<P>
For equation 2:  0 = -x-4 --->x=-4 and y = -(0) -4 ---> y=-4.  The points are (0,-4) and (-4,0)<P>
In each case, connect the two points.  You'll see the two lines are parallel.  They never intersect, so this system has no solutions.
{{{ graph( 300, 200, -6, 5, -10, 10, y=4-x,y= -1x-4 )}}}