Graphing systems of inequalities

Linear inequalities are graphed as lines. There are usually two to four sets of linear inequalities in a graph. When shading in parts of the graph, one must plug in a single x-y coordinate to each equation in the set. If the result is true, then you shade the side of the line that contains the point. If it is not true, then you shade the opposite side.  Each line must go through this shading process.  Whichever potion of the plane contains shaded areas from both the lines is the "answer".