document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=697428>Question 697428</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The monthly cost (in dollars) of water use (in dollars) is a linear function of the amount of water used (in hundreds of cubic feet, HCF). The cost for using 17 HCF of water is $34.47  , and the cost for using 45 HCF is $80.67 . What is the cost for using 25 HCF of water? <BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #429988 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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/cgi-bin/show-face.mpl?user=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=429988\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Basically, they are giving you 2 points on a graph, and<BR>\n" );
document.write( "they want you to find a 3rd point.<BR>\n" );
document.write( "Plot hundreds of ft3 ( HFC ) on the horizontal axis<BR>\n" );
document.write( "and Monthly cost on the vertical axis.<BR>\n" );
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document.write( "Given:<BR>\n" );
document.write( "( 17, 34.47 ) and<BR>\n" );
document.write( "( 45, 80.67 )<BR>\n" );
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document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+ ALIGN=MIDDLE  ALT=\"+c+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = Monthly cost of water use<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h+ ALIGN=MIDDLE  ALT=\"+h+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = HFC's of water<BR>\n" );
document.write( "------------<BR>\n" );
document.write( "Use the general point-slope formula<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+c+-+34.47+%29+%2F+%28+h+-+17+%29+=+%28+80.67+-+34.47+%29+%2F+%28+45+-+17+%29+ ALIGN=MIDDLE  ALT=\"+%28+c+-+34.47+%29+%2F+%28+h+-+17+%29+=+%28+80.67+-+34.47+%29+%2F+%28+45+-+17+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+c+-+34.47+%29+%2F+%28+h+-+17+%29+=+46.2+%2F+28+ ALIGN=MIDDLE  ALT=\"+%28+c+-+34.47+%29+%2F+%28+h+-+17+%29+=+46.2+%2F+28+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+28%2A%28+c+-+34.47+%29+=+46.2%2A%28+h+-+17+%29+ ALIGN=MIDDLE  ALT=\"+28%2A%28+c+-+34.47+%29+=+46.2%2A%28+h+-+17+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+28c+-+965.16+=+46.2h+-+785.4+ ALIGN=MIDDLE  ALT=\"+28c+-+965.16+=+46.2h+-+785.4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+28c+=+46.2h+%2B+179.76+ ALIGN=MIDDLE  ALT=\"+28c+=+46.2h+%2B+179.76+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+1.65h+%2B+6.42+ ALIGN=MIDDLE  ALT=\"+c+=+1.65h+%2B+6.42+\"   DISABLED_style= \"max-width:90%; height:auto;\" > answer<BR>\n" );
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document.write( "check answer:<BR>\n" );
document.write( "Does the line include ( 45, 80.67 )<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+1.65h+%2B+6.42+ ALIGN=MIDDLE  ALT=\"+c+=+1.65h+%2B+6.42+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+80.67+=+1.65%2A45+%2B+6.42+ ALIGN=MIDDLE  ALT=\"+80.67+=+1.65%2A45+%2B+6.42+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+80.67+=+74.25+%2B+6.42+ ALIGN=MIDDLE  ALT=\"+80.67+=+74.25+%2B+6.42+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+80.67+=+80.67+ ALIGN=MIDDLE  ALT=\"+80.67+=+80.67+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK- you can check ( 17, 34.47 )<BR>\n" );
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document.write( "What is the cost for using 25 HCF of water? <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+1.65%2A25+%2B+6.42+ ALIGN=MIDDLE  ALT=\"+c+=+1.65%2A25+%2B+6.42+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+41.25+%2B+6.42+ ALIGN=MIDDLE  ALT=\"+c+=+41.25+%2B+6.42+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+47.67+ ALIGN=MIDDLE  ALT=\"+c+=+47.67+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The cost is $47.67 \r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
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