Algebra.Com's Answer #197012 by Edwin McCravy(20056)![\"\"](\"/images/stars/stars-13.gif\")  
You can put this solution on YOUR website!
How do you solve:\r
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document.write( "Write an equation of a line which contains the points (3, -2) and (3,6).\r
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document.write( "Let's plot those two points:\r\n" );
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document.write( "Now I will draw a green line through them:\r\n" );
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document.write( "Hmm! That's a very special type of line!\r\n" );
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document.write( "Notice that it is VERICAL. Vertical lines are the only kinds of lines \r\n" );
document.write( "that DO NOT have slopes or y-intercepts! \r\n" );
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document.write( "However, vertical lines DO have equations. Notice that the \r\n" );
document.write( "two points you were given both have the same x-coordinate 3.\r\n" );
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document.write( "Look at some other points on that vertical line. Five more\r\n" );
document.write( "points on that line are (3,5), (3,4), (3,2), (3,-3), and (3,-7):\r\n" );
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document.write( "In fact, EVERY point on that line has its x-coordinate\r\n" );
document.write( "as 3. \r\n" );
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document.write( "So to describe that vertical green line, we could just say\r\n" );
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document.write( "\"The x-coordinate of any point on the line always equals 3\"\r\n" );
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document.write( "or\r\n" );
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document.write( "\"x always equals 3\"\r\n" );
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document.write( "or even shorter\r\n" );
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document.write( "\"x = 3\"\r\n" );
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document.write( "That's the way to describe a vertical line, just\r\n" );
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document.write( "write \"x =\" and put whatever number after it\r\n" );
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document.write( "that the x-coordinates of all the points on it are,\r\n" );
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document.write( "in this case all the x-coordinates are 3.\r\n" );
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document.write( "So the equation of that vertical line is\r\n" );
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document.write( "x = 3\r\n" );
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document.write( "You cannot put it in slope-intercept form, \r\n" );
document.write( "for two reasons:\r\n" );
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document.write( "1. It has no slope!\r\n" );
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document.write( "and\r\n" );
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document.write( "2. It has no y-intercept!\r\n" );
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document.write( "So you just have to leave the equation as simply\r\n" );
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document.write( "x = 3\r\n" );
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document.write( "Note:\r\n" );
document.write( "The problem you have submitted is an unusual kind of problem\r\n" );
document.write( "because every other kind of line except a vertical line has\r\n" );
document.write( "a slope and a y-intercept. All vertical lines have equations \r\n" );
document.write( "of the form x = k \r\n" );
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document.write( "Edwin \r
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