document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=120991>Question 120991</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What would be the slope and y-intercept in the following equation: x = -8? I got: Slope: 0; y-intercept: none. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #88787 by </B><A HREF=/tutors/aboutme.mpl?userid=bucky><B>bucky(2189)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=bucky><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=88787\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> You were on the right track, but a little bit in error on how you interpreted the slope.<BR>\n" );
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document.write( "Go back to the definition of slope ... slope is the change in y divided by the corresponding<BR>\n" );
document.write( "change in x.  When you say that x = -8 that tells you that the change in x is zero ... x is<BR>\n" );
document.write( "always -8 regardless of what the value of y is.  But if the change in x is zero, then the<BR>\n" );
document.write( "definition of slope becomes \"the change in y divided by zero.\" And algebra tells us that<BR>\n" );
document.write( "division by zero is not allowed. Therefore, the slope is undefined for this problem.<BR>\n" );
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document.write( "If the slope was zero, then the graph would be a horizontal line, and there would then have<BR>\n" );
document.write( "to be a y-intercept. But you were correct when you said that the y-intercept is none. Why is<BR>\n" );
document.write( "that the case? It is because the graph of x = -8 is a vertical line ... a line of undefined<BR>\n" );
document.write( "slope.<BR>\n" );
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document.write( "The following graph shows in \"brown-red\" color the graph of x = -8.  You can see that it<BR>\n" );
document.write( "is perpendicular to the x-axis and, therefore, cannot intercept the y-axis. I've added as a<BR>\n" );
document.write( "green graph an example of a line that has zero slope just to show you the difference<BR>\n" );
document.write( "between an undefined slope and a zero slope.<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28400%2C400%2C-10%2C10%2C-20%2C20%2C6000%28x%2B8%29%2C3%29 ALIGN=MIDDLE  ALT=\"graph%28400%2C400%2C-10%2C10%2C-20%2C20%2C6000%28x%2B8%29%2C3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Hope this helps you to see the correct interpretation of an equation that says x equals some<BR>\n" );
document.write( "constant value.<BR>\n" );
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