document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1173444>Question 1173444</A>: <I><SPAN STYLE=\"word-break: break-all;\"> what is the equation of the line that passes through the point (-4,7) and has an undefined slope? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #798644 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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/cgi-bin/show-face.mpl?user=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=798644\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> an undefined slope means that the line is vertical.\r<BR>\n" );
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document.write( "if the line is vertical, then the equation is x = -4\r<BR>\n" );
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document.write( "the value of x is -4 and there are an infinite number of values of y that satisfy the equation, (-4,7) being one of them.\r<BR>\n" );
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document.write( "consider the equation for the slope of the line.\r<BR>\n" );
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document.write( "the slope is equal to (y2 - y1) / (x2 - x1).\r<BR>\n" );
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document.write( "if (x2 - x1) is equal to 0, then the slope is undefined.\r<BR>\n" );
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document.write( "if (x2 - x1) is equal to 0, then x2 must be equal to x1.\r<BR>\n" );
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document.write( "this means that you have a different value of y for the same value of x.\r<BR>\n" );
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document.write( "this can only occur if the line is perpendicular.\r<BR>\n" );
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document.write( "if the line is perpendicular, then the equation becomes x = c\r<BR>\n" );
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document.write( "c can be any constant.\r<BR>\n" );
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document.write( "this means that there are an infinite number of possibilities for the value of y.\r<BR>\n" );
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document.write( "here's a graph with a couple of examples of points that are on the line.\r<BR>\n" );
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document.write( "you can see that there are multiple values of y for the line x = -4, with y = 7 being one of them.\r<BR>\n" );
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