document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=159071>Question 159071</A>: <I><SPAN STYLE=\"word-break: break-all;\"> please answer this question: the average cost of tuition fees, room and board for 2 year institution increased from $1979 in 1980 to $4895 in 1997.\r<BR>\n" );
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document.write( "A) find the linear function that will give average expense of a two year institution E, as a function of time, x, where x is defined to be the number of years since 1980.\r<BR>\n" );
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document.write( "B) use the equation to predict the average expense associated with 2010.\r<BR>\n" );
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document.write( "i tried to find the linear function but i got stuck i been here for hours and i could figure it out. i got E=17x+1979-4895 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #117153 by </B><A HREF=/tutors/aboutme.mpl?userid=vleith><B>vleith(2983)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=vleith><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=117153\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let's do this.<BR>\n" );
document.write( "We'll setup a linear equation in the form y = mx +b that uses the given info.<BR>\n" );
document.write( "y is the cost of tuition<BR>\n" );
document.write( "x is the number of years after 1980\r<BR>\n" );
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document.write( "You are given : $1979 in 1980 to $4895 in 1997. So you know 2 points on the line. Thise points are {0, 1979) and (17, 4985). We find the x values as <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+year+-+1980 ALIGN=MIDDLE  ALT=\"x+=+year+-+1980\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "First let's find the slope of the line<BR>\n" );
document.write( "m = (y[2] - y[1])/(x[2] - x(1])<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m+=+%284985+-+1979%29%2F%2817+-0%29 ALIGN=MIDDLE  ALT=\"m+=+%284985+-+1979%29%2F%2817+-0%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m+=+3006%2F17 ALIGN=MIDDLE  ALT=\"m+=+3006%2F17\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m+=+176.8 ALIGN=MIDDLE  ALT=\"m+=+176.8\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "b is the y intercept. That is the point where the x value is 0. So for us <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+=+1979 ALIGN=MIDDLE  ALT=\"b+=+1979\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "We have what we need. Just plug it all in<BR>\n" );
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" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+176.8+%2A+x+%2B+1979 ALIGN=MIDDLE  ALT=\"y+=+176.8+%2A+x+%2B+1979\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Check the eqaution using the two points you know. At year 1980, x =0, so y = 1979. That is correct\r<BR>\n" );
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document.write( "At year 1997, x = 17. So <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+176.8+%2A+17+%2B+1797 ALIGN=MIDDLE  ALT=\"y+=+176.8+%2A+17+%2B+1797\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4984.6 ALIGN=MIDDLE  ALT=\"4984.6\"   DISABLED_style= \"max-width:90%; height:auto;\" > close enough\r<BR>\n" );
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document.write( "So for part A) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=E+=+176.8+%2A+x+%2B+1979 ALIGN=MIDDLE  ALT=\"E+=+176.8+%2A+x+%2B+1979\"   DISABLED_style= \"max-width:90%; height:auto;\" >  (same equation, just use the variables the problem states.\r<BR>\n" );
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document.write( "Finally, you are asked to estimate the cost in the year 2010.<BR>\n" );
document.write( "In 2010 <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+2010+-+1980 ALIGN=MIDDLE  ALT=\"x+=+2010+-+1980\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=30 ALIGN=MIDDLE  ALT=\"30\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Plugging that into <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+176.8+%2A+x+%2B+1979 ALIGN=MIDDLE  ALT=\"y+=+176.8+%2A+x+%2B+1979\"   DISABLED_style= \"max-width:90%; height:auto;\" > yeilds<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+176.8+%2A+30+%2B+1979 ALIGN=MIDDLE  ALT=\"y+=+176.8+%2A+30+%2B+1979\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+5304+%2B+1979 ALIGN=MIDDLE  ALT=\"y+=+5304+%2B+1979\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+7283 ALIGN=MIDDLE  ALT=\"y+=+7283\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " </SPAN>\n" );
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