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document.write( "Let x = the number of refrigerators\r\n" );
document.write( "Let y = the number of upright pianos\r\n" );
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\r\n" );
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document.write( "We graph the boundary line:\r\n" );
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document.write( "

\r\n" );
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document.write( "Divide through by 25 to simplify:\r\n" );
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document.write( "

\r\n" );
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document.write( "The intercepts are
and
\r\n" );
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document.write( "We draw the boundary line, and shade below it because the\r\n" );
document.write( "origin used as a test point:\r\n" );
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document.write( "

\r\n" );
document.write( "

\r\n" );
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document.write( "gives a true inequality\r\n" );
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\r\n" );
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document.write( "Will 10 refrigerators and 9 pianos overload the truck?\r\n" );
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document.write( "The points inside or on the boundary of the shaded region\r\n" );
document.write( "represent the loads the truck can carry. The x-coodinate\r\n" );
document.write( "is the number of refrigerators, and the y-coordinate is\r\n" );
document.write( "the number of pianos.\r\n" );
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document.write( "We plot the point (10,9) and see if it is in the shaded region:\r\n" );
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document.write( "
\r\n" );
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document.write( "The point (10,9) is outside the shaded region, so yes,\r\n" );
document.write( "10 refrigerators and 9 pianos will overload the truck.\r\n" );
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document.write( "Edwin
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document.write( "