document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=282706>Question 282706</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If i needed 2 points to be in Y intercept form, what would the answer be for (-5,2) and (4,1)?<BR>\n" );
document.write( "y=mx+b should bt the form. Thanks. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #205239 by </B><A HREF=/tutors/aboutme.mpl?userid=oberobic><B>oberobic(2304)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=oberobic><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=205239\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> y = mx+b is slope-intercept form, where<BR>\n" );
document.write( "m = slope<BR>\n" );
document.write( "b = y-intercept (defined by x=0)<BR>\n" );
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document.write( "Two points can be used to draw a line.<BR>\n" );
document.write( "(-5,2) and (4,1)<BR>\n" );
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document.write( "You also can determine the slope by computing the rise over the run.<BR>\n" );
document.write( "rise = change in y = y<sub>2</sub> - y<sub>1</sub><BR>\n" );
document.write( "run = change in x = x<sub>2</sub> - x<sub>1</sub><BR>\n" );
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document.write( "We can define either point what we want, but we have to keep consistent.<BR>\n" );
document.write( "(x<sub>1</sub>, y<sub>1</sub>) = (-5, 2)<BR>\n" );
document.write( "(x<sub>2</sub>, y<sub>2</sub>) = (4, 1)<BR>\n" );
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document.write( "rise = 1-2 = -1<BR>\n" );
document.write( "run = 4 -(-5) = 4+5 = 9<BR>\n" );
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document.write( "So,<BR>\n" );
document.write( "m = -1/9<BR>\n" );
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document.write( "That means y= -1/9x + b<BR>\n" );
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document.write( "Now we have to compute 'b' to ensure it goes through the points given.<BR>\n" );
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document.write( "We know that when x=4, y=1<BR>\n" );
document.write( "Substituting, we find 'b'<BR>\n" );
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document.write( "1 = -1/9*4 + b<BR>\n" );
document.write( "1 + 4/9 = b<BR>\n" );
document.write( "9/9 + 4/9 = b<BR>\n" );
document.write( "13/9 = b<BR>\n" );
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document.write( "So, we now have the equation:  y = -1/9x + 13/9<BR>\n" );
document.write( "Slope = -1/9<BR>\n" );
document.write( "y-intercept = (0, 13/9)<BR>\n" );
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document.write( "The x-intercept occurs where y=0, so we can solve by substitution again.<BR>\n" );
document.write( "0 = -1/9x + 13/9<BR>\n" );
document.write( "The obvious answer is x=13, so the point is (13,0).<BR>\n" );
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document.write( "Graphing is a good way to check your work.<BR>\n" );
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