document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=91101>Question 91101</A>: <I><SPAN STYLE=\"word-break: break-all;\"> My question is: Why is line x=4 a vertical line?\r<BR>\n" );
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document.write( "Thanks. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #66125 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=66125\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Since x=4, our x values will always be x=4. So the only thing that will change is the y-value. Lets plot some points for the equation x=4\r<BR>\n" );
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document.write( "Plot the point in (4,-5) (note: we can start at any y value)\r<BR>\n" );
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document.write( "Now add the point in (4,-4):\r<BR>\n" );
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document.write( "Now add the point in (4,-3):\r<BR>\n" );
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document.write( "Now add the point in (4,-2):\r<BR>\n" );
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document.write( "Now add the point in (4,-1):\r<BR>\n" );
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document.write( "Now add the point in (4,0):\r<BR>\n" );
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document.write( "Now add the point in (4,1):\r<BR>\n" );
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document.write( "Now add the point in (4,2):\r<BR>\n" );
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document.write( "Now add the point in (4,3):\r<BR>\n" );
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document.write( "Now add the point in (4,4):\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=drawing%28500%2C500%2C-5%2C5%2C-5%2C5%2C%0D%0Agrid%28+1+%29%2C%0D%0Acircle%284%2C-5%2C0.05%29%2C%0D%0Acircle%284%2C-5%2C0.05%29%2C%0D%0Acircle%284%2C-4%2C0.05%29%2C%0D%0Acircle%284%2C-4%2C0.05%29%2C%0D%0Acircle%284%2C-3%2C0.05%29%2C%0D%0Acircle%284%2C-3%2C0.05%29%2C%0D%0Acircle%284%2C-2%2C0.05%29%2C%0D%0Acircle%284%2C-2%2C0.05%29%2C%0D%0Acircle%284%2C-1%2C0.05%29%2C%0D%0Acircle%284%2C-1%2C0.05%29%2C%0D%0Acircle%284%2C0%2C0.05%29%2C%0D%0Acircle%284%2C0%2C0.05%29%2C%0D%0Acircle%284%2C1%2C0.05%29%2C%0D%0Acircle%284%2C1%2C0.05%29%2C%0D%0Acircle%284%2C2%2C0.05%29%2C%0D%0Acircle%284%2C2%2C0.05%29%2C%0D%0Acircle%284%2C3%2C0.05%29%2C%0D%0Acircle%284%2C3%2C0.05%29%2C%0D%0Acircle%284%2C4%2C0.05%29%2C%0D%0Acircle%284%2C4%2C0.05%29%0D%0A%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Now add the point in (4,5):\r<BR>\n" );
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document.write( "We can see that the points form a vertical line. So that means x=4 is a vertical line through x=4\r<BR>\n" );
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document.write( "As a general rule, any equation <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x=n ALIGN=MIDDLE  ALT=\"x=n\"   DISABLED_style= \"max-width:90%; height:auto;\" > is a vertical line through x=n </SPAN>\n" );
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