document.write( "Question 968345: determine whether the point (-4,3) lies on the graph of x-2y=11
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Algebra.Com's Answer #591742 by Edwin McCravy(20077) $\"\"$ $\"About$

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determine whether the point (-4,3) lies on the graph of x-2y=11
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document.write( "The first coordinate -4 is the value for x.\r\n" );
document.write( "The second coordinate 3 is the value for y.\r\n" );
document.write( "[The coordinates are in alphabetical order, x first and y second.\r\n" );
document.write( "That's a very important thing to know.]\r\n" );
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document.write( "Substitute (-4) for x and (3) for y in the equation and simplify.\r\n" );
document.write( "If it comes out a true statement, then (-4,3) is a solution, and\r\n" );
document.write( "it represents a point on the line. If it turns out false, it is \r\n" );
document.write( "not a solution, and does not represent a point on the line:\r\n" );
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document.write( "    x-2y = 11\r\n" );
document.write( "(-4)-2(3)=11\r\n" );
document.write( "     -4-6=11\r\n" );
document.write( "      -10=11\r\n" );
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document.write( "That's clearly false, so (-4,3) does not lie on the graph of x-2y = 11.\r\n" );
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document.write( "Here is a graph of the line x-2y=11 and the point (-4,3)\r\n" );
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document.write( "[Notice that there was a reason they gave you the point (-4,3).  \r\n" );
document.write( "The reason they gave you that is because the point (3,-4) IS on \r\n" );
document.write( "the line, and students who get x and y backwards would think it \r\n" );
document.write( "was on the line, and get the problem wrong. \r\n" );
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document.write( "Look what happens when you substitute x=3, and y=-4 instead:\r\n" );
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document.write( "     x-2y = 11\r\n" );
document.write( "(3)-2(-4) = 11\r\n" );
document.write( "      3+8 = 11\r\n" );
document.write( "       11 = 11\r\n" );
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document.write( "That is true, so the point (3,-4) IS on the line as you can see below:\r\n" );
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document.write( "But the point (-4,3) in NOT on the line.\r\n" );
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document.write( "Edwin

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