document.write( "Question 356324: Name three points on the line represented by x=4. Then explain why, when we connect these points, the line goes straight up and down and does not slant to the left or right. \n" ); document.write( "
Algebra.Com's Answer #254380 by Edwin McCravy(20055)\"\" \"About 
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document.write( "Here's the line (in green) whose equation is x = 4:\r\n" );
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document.write( "Here are three points on that line:\r\n" );
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document.write( "Look at all those ordered pairs, labels for points, (4,8), (4,-6), and (4,3).\r\n" );
document.write( "See all those 4's?  All three have a 4 for their x coordinate.  Did you know\r\n" );
document.write( "that's why the equation x = 4 is the equation of that vertical green line?  The\r\n" );
document.write( "equation \"x equals 4\" just tells us what is true about every ordered pair\r\n" );
document.write( "representing a point on that line.  \r\n" );
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document.write( "                   x = 4\r\n" );
document.write( "just says:\r\n" );
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document.write( "               x is always equal to 4\r\n" );
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document.write( "which means:\r\n" );
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document.write( "        The x-coordinate of every point on that green line = 4\r\n" );
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document.write( "That's why x = 4 is its equation.  It tells us what is true about the \r\n" );
document.write( "x-coordinate of every point on that line.  We can't say that about\r\n" );
document.write( "any other line except that green one.\r\n" );
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\n" ); document.write( "Why does the line goes straight up and down and does not slant to the left or right?
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document.write( "Because if it slanted to the left or right, its x-coordinates would not be all\r\n" );
document.write( "equal to 4 like they are on the green line above.  If we drew a slanted green\r\n" );
document.write( "line like this:\r\n" );
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document.write( "We couldn't say all the ordered pairs which represent points on that graph\r\n" );
document.write( "have their x-axis equal to 4. Because as you see, those points have all\r\n" );
document.write( "different x-coordinates.  And they are determined by a different equation.\r\n" );
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document.write( "All the points which have their x-coordinates equal to 4 are all on that\r\n" );
document.write( "vertical line and none of them are anywhere else.  That's why \"x = 4\" is\r\n" );
document.write( "all you need to tell the story about every point on that line having its\r\n" );
document.write( "x-coordinate equal to 4.\r\n" );
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document.write( "Edwin

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