\r\n" );
document.write( "y < |4-x|\r\n" );
document.write( "\r\n" );
document.write( "First we draw the graph of the boundary equation which is\r\n" );
document.write( "\r\n" );
document.write( "y = |4-x| \r\n" );
document.write( "\r\n" );
document.write( "and since < does not include equality we must draw\r\n" );
document.write( "\r\n" );
document.write( "the graph dotted:\r\n" );
document.write( "\r\n" );
document.write( "
\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Next we only need to find out whether the solutions are all below\r\n" );
document.write( "the graph or above it. To find out we pick any test point which\r\n" );
document.write( "is not on the graph. The easiest test point is the origin (0,0)\r\n" );
document.write( "and since it is not on the graph, but below the graph, we can use\r\n" );
document.write( "it as a test poin, So we substitute (x,y) = (0,0) in\r\n" );
document.write( "\r\n" );
document.write( "y < |4-x|\r\n" );
document.write( "\r\n" );
document.write( "0 < |4-0|\r\n" );
document.write( "\r\n" );
document.write( "0 < |4|\r\n" );
document.write( "0 < 4\r\n" );
document.write( "That is true and that nmeans that the origin is a solution, and \r\n" );
document.write( "since the origin is below the graph, all solutions are below the \r\n" );
document.write( "graph, so we shade the area below the line, and the final graph \r\n" );
document.write( "is this:\r\n" );
document.write( "\r\n" );
document.write( "
\r\n" );
document.write( "\r\n" );
document.write( "Edwin
\n" );
document.write( "![\"\"](\"/images/stars/stars-13.gif\")
