Work Step by Step
Since the form of the equation is $y > mx+b$, the graph would be shaded above the dotted line. If $m$ is positive, then (1,2) would be above the line while (3,2) is below the line. However, we are told (1,2) is not part of the solution set (while (3,2) is part of the solution set). Thus, the slope must be negative.