document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=550022>Question 550022</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find an equation in slope-intercept form passing through the points (-6.2,18.1) and (-3.4,18.1). </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #358328 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=358328\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This one might be a little confusing to you.<BR>\n" );
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document.write( "Normally, the slope 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%2Bb ALIGN=MIDDLE  ALT=\"y+=+mx%2Bb\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
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document.write( "in which m, the multiplier of x, is the slope and b is the value on the y-axis where the linear graph of the equation crosses the y-axis.<BR>\n" );
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document.write( "The slope is normally computed by dividing the change in x from the two given points into the corresponding change in y. In this case, note that in the two points that are given, x goes from -6.2 in one of the points to - 3.4 in the other. Subtracting the -6.2 from -3.4 results in a difference of +2.8. So in finding the slope, +2.8 is what we'll be dividing into the corresponding change in the y values of the two points. <BR>\n" );
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document.write( "But, what is the change in y? The value of y in the first point is 18.1 and the value of y in the second point is also 18.1. The difference in these two values is zero. So while x went 2.8 units toward the right (the run from -6.1 to -3.4) the value of y stayed the same and, therefore, the rise was zero. Dividing 2.8 into zero results in a slope of zero.<BR>\n" );
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document.write( "Return to the the slope-intercept form for the equation. When you substitute zero for the slope the equation becomes:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+0%2Ax+%2B+b ALIGN=MIDDLE  ALT=\"y+=+0%2Ax+%2B+b\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "The multiplication by zero makes the x term disappear and we are left with:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+b ALIGN=MIDDLE  ALT=\"y+=+b\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Now all we have to realize is that y never changes regardless of what value we choose for x. For this problem the value of y is always 18.1 and the graph is a horizontal line (parallel to the x-axis) that crosses the y-axis at +18.1. This means that b is 18.1 and the slope intercept equation is simply:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+18.1 ALIGN=MIDDLE  ALT=\"y+=+18.1\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "That's all there is to it. Whenever you see a slope intercept form that says simply y equals a constant, you should picture a graph that is a horizontal line and crosses the y-axis at the value of the constant.<BR>\n" );
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document.write( "Hope this helps you to understand the \"trick\" in this problem and what it means.<BR>\n" );
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