document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=70625>Question 70625</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Can you please help on this problem, rather complicated...instructions..write the equation of the line passing through (5,5) and (4,5). </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #50413 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=50413\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This is a \"trick\" question, so you need to be a little careful with it.  It usually is<BR>\n" );
document.write( "helpful to make a rough sketch of the x and y-axes and then plot the points, just to help<BR>\n" );
document.write( "visualize the slope of the line.  Then we could proceed to use the slope-intercept form of an<BR>\n" );
document.write( "equation ... y = mx + b ... where m is the slope and b is the point at which the graph crosses<BR>\n" );
document.write( "the y-axis.<BR>\n" );
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document.write( "But in this case something unusual happens when you try to calculate the slope.<BR>\n" );
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document.write( "For the two given points (5,5) and (4,5) you can identify the first point as (x1,y1).<BR>\n" );
document.write( "And you can identify the second point as (x2,y2).  By comparing each given point to its<BR>\n" );
document.write( "corresponding form you can see that: x1=5, y1=5, x2=4, and y2=5.  Now write the equation for<BR>\n" );
document.write( "finding the slope (m) if you know two points on the line.  This equation is:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m=%28y2-y1%29%2F%28x2-x1%29 ALIGN=MIDDLE  ALT=\"m=%28y2-y1%29%2F%28x2-x1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Now plug in the values for x1, y1, x2, and y2.  When you do the slope equation becomes:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m=%285-5%29%2F%284-5%29 ALIGN=MIDDLE  ALT=\"m=%285-5%29%2F%284-5%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "But look at the numerator. 5 minus 5 is zero.  The denominator equals -1.  And when you<BR>\n" );
document.write( "divide -1 into zero, the answer is zero.  What does a slope equal to zero mean? If a line<BR>\n" );
document.write( "has a slope of zero, it does not go upward or downward.  It just stays horizontal.<BR>\n" );
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document.write( "So the graph is a horizontal line.  It has the same value for y regardless of the value<BR>\n" );
document.write( "for x.  If you think about it a little bit, for this problem you will see that the line<BR>\n" );
document.write( "goes across the y-axis at +5 and it runs in both directions as far as you want.  Whatever<BR>\n" );
document.write( "value you chose for x, y is always +5 units above the x-axis.  And the equation for this <BR>\n" );
document.write( "situation is y = +5.  That's your answer ... choose any value on the x-axis and the corresponding<BR>\n" );
document.write( "value of y is always +5.<BR>\n" );
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document.write( "Think about it a little bit and it will make sense.  Also your sketch would have shown you<BR>\n" );
document.write( "that the line was probably horizontal and then you could have verified that by using the<BR>\n" );
document.write( "slope equation.<BR>\n" );
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