Just plot the points on the graph so if x+y=-6 just make a list of all of the points that will work (remember that the left-to-right line is x and the up-to-down line is y, and right and up is positive and left and down is negative)
so make a list (in graphs we write [x,y] or (x,3)) so here are some points that will work (-3,-3) (-4,-2) (-2,-4) (-1,-5) (-5,-1) (0,-6) (-6,0) (-7,1) (1,-7) and so on, just plot those points and more that will work for x+y=-6 and you should be good,
there is another way that this is supposed to be done but this way is easier
