4x-y>=-4
this describes a line separating the valid & invalid sides, so change it into a more typical form (y=mx+b):
4x-y>=-4
-y>=-4-4x
y<=4x+4
so it intercepts y at y=4 and ascends by 4 per x -> insert some x values -> Points (0,4) and (-1,0) or (2,8)
which side of the line is the valid area? everything below it, because of y <= ...