document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=78913>Question 78913</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How do I write the equation of the line that passes through point (-1,-2) with a slope of -7. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #56584 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=56584\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Given a line through the point (-1,-2) with a slope of -7. Write an equation for the line.<BR>\n" );
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document.write( "There are several ways that this can be done. One way is to use the equation:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m+=+%28y+-+y%5B1%5D%29%2F%28x+-+x%5B1%5D%29 ALIGN=MIDDLE  ALT=\"m+=+%28y+-+y%5B1%5D%29%2F%28x+-+x%5B1%5D%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "in which m is the slope and the values of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%5B1%5D ALIGN=MIDDLE  ALT=\"x%5B1%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y%5B1%5D ALIGN=MIDDLE  ALT=\"y%5B1%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" > come from the x and y<BR>\n" );
document.write( "values of the point you were given. Substituting those values gives you the equation:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-7+=+%28y+-+%28-2%29%29%2F%28x+-+%28-1%29%29 ALIGN=MIDDLE  ALT=\"-7+=+%28y+-+%28-2%29%29%2F%28x+-+%28-1%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
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document.write( "This simplifies to:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-7+=+%28y++%2B+2%29%2F%28x+%2B+1%29 ALIGN=MIDDLE  ALT=\"-7+=+%28y++%2B+2%29%2F%28x+%2B+1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
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document.write( "and that is one form of an equation for the line.<BR>\n" );
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document.write( "Another way you can do it is to use the slope-intercept form of an equation. The slope<BR>\n" );
document.write( "intercept form is:<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( "where m is the slope of the line and b is the value where the graph crosses the y axis.<BR>\n" );
document.write( "In this case you were told that the slope was -7. So you can substitute that value for<BR>\n" );
document.write( "m in the slope intercept form to get:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-7x+%2B+b ALIGN=MIDDLE  ALT=\"y+=+-7x+%2B+b\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "From the point you were given on the graph you know that the equation is true when<BR>\n" );
document.write( "x =  -1 and y = -2.  Substitute those two values into the slope intercept form and you<BR>\n" );
document.write( "get:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-2+=+-7%28-1%29+%2B+b ALIGN=MIDDLE  ALT=\"-2+=+-7%28-1%29+%2B+b\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "by doing the multiplication on the right side this equation becomes:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-2+=+7+%2B+b ALIGN=MIDDLE  ALT=\"-2+=+7+%2B+b\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Subtract 7 from both sides and you have solved for b.  When you do that subtraction<BR>\n" );
document.write( "you get:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-2+-+7+=+b ALIGN=MIDDLE  ALT=\"-2+-+7+=+b\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "which simplifies to <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+=+-9 ALIGN=MIDDLE  ALT=\"b+=+-9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Return to the slope intercept form we were working on:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-7x+%2B+b ALIGN=MIDDLE  ALT=\"y+=+-7x+%2B+b\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "and substitute -9 for b to get:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-7x+-9 ALIGN=MIDDLE  ALT=\"y+=+-7x+-9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "and this also is an equation for the graph you were given.  Believe it or not, if you<BR>\n" );
document.write( "take our first answer and manipulate it around, you can work it into this same answer of<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-7x+-9 ALIGN=MIDDLE  ALT=\"y+=+-7x+-9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Hope this helps you to understand a couple of ways to get the equation of a line when you<BR>\n" );
document.write( "are given the slope of the line and a point on the line.<BR>\n" );
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