document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=80954>Question 80954</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Write the equation of the line with slope –2 and y-intercept (0, 0).  Then graph the line. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #58081 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=58081\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> For this problem you can use the slope-intercept equation.  This equation has the form:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+mx+%2B+b ALIGN=MIDDLE  ALT=\"y+=+mx+%2B+b\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "In this equation m represents the slope and b is the value on the y-axis where the graph <BR>\n" );
document.write( "intersects the y-axis.<BR>\n" );
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document.write( "In this problem you are told that the slope is -2. And you are told that the graph goes through<BR>\n" );
document.write( "the origin. This means that the graph intersects the y-axis at a y value of 0. This translates<BR>\n" );
document.write( "to m = -2 and b = 0.  Substituting these values into the slope-intercept equation results in <BR>\n" );
document.write( "the equation becoming\"<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-2x+%2B+0 ALIGN=MIDDLE  ALT=\"y+=+-2x+%2B+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "You can then simplify it by dropping the 0 to get the equation:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-2x ALIGN=MIDDLE  ALT=\"y+=+-2x\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "The fact that the slope is negative tells you that the graph goes down as you move to <BR>\n" );
document.write( "the right.<BR>\n" );
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document.write( "You can now get some points on the graph by assigning values to x and computing the corresponding<BR>\n" );
document.write( "values of y.  For example, let x = -5. Plug that value in for x and the equation becomes:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-2%2A-5+=+10 ALIGN=MIDDLE  ALT=\"y+=+-2%2A-5+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "So when x is -5, then y = +10. This means the point (-5, +10) is on the graph.<BR>\n" );
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document.write( "The problem tells you that (0, 0) is on the graph.<BR>\n" );
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document.write( "Then suppose that we let x = +5.  Substituting this value into the equation results in:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-2%2A5+=+-10 ALIGN=MIDDLE  ALT=\"y+=+-2%2A5+=+-10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "This means that when x equals +5, the corresponding value of y is -10.  So the point<BR>\n" );
document.write( "(+5, -10) is on the graph.  If you plot these three points you should see that they <BR>\n" );
document.write( "lie on a straight line.  Take a straight edge and line it on these points. Then extend a <BR>\n" );
document.write( "line through all three points.  When you do you should have a graph that looks like:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28300%2C300%2C-15%2C15%2C-15%2C15%2C-2%2Ax%29 ALIGN=MIDDLE  ALT=\"graph%28300%2C300%2C-15%2C15%2C-15%2C15%2C-2%2Ax%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Hope this helps you to understand the problem and see how to get an answer.<BR>\n" );
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document.write( "Cheers<BR>\n" );
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