Question 37362
Well for no solution to exist, the lines that govern them would need to be parallel and the shaded half-planes would have to be in opposite directions so that there is no overlapping of shaded areas.  They could even represent the same line as long as they are both dotted and are shaded oppositely.  For a system of inequalities to have a solution in the first quadrant, both (or all) shaded half-planes must intersect somewhere in the first quadrant.