document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=127224>Question 127224</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Natural Gas. The cost of 1000 cubic feet of natural gas is $39 and the cost of 3000 cubic feet is $99 There is a linear equation that expressed the cost C in terms of the numberof cubic feet n. Find the equation and find the cost of 2400 cubic feet of natural gas. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #93204 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=93204\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If cubic feet of gas is plotted on the horizontal axis<BR>\n" );
document.write( "and the corresponding cost on the vertical axis,<BR>\n" );
document.write( "we are given 2 points, (1000, 39) and (3000,99)<BR>\n" );
document.write( "There is a formula you can use<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28y%5B2%5D+-+y%5B1%5D%29+%2F+%28x%5B2%5D+-+x%5B1%5D%29+=+%28y+-+y%5B1%5D%29+%2F+%28x+-+x%5B1%5D%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "the given points are (x[2],y[2]) and (x[1],y[1])<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%2899+-+39%29+%2F+%283000+-+1000%29+=+%28y+-+39%29+%2F+%28x+-+1000%29 ALIGN=MIDDLE  ALT=\"%2899+-+39%29+%2F+%283000+-+1000%29+=+%28y+-+39%29+%2F+%28x+-+1000%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=60+%2F+2000+=+%28y+-+39%29+%2F+%28x+-+1000%29 ALIGN=MIDDLE  ALT=\"60+%2F+2000+=+%28y+-+39%29+%2F+%28x+-+1000%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3%2F100+=+%28y+-+39%29+%2F+%28x+-+1000%29 ALIGN=MIDDLE  ALT=\"3%2F100+=+%28y+-+39%29+%2F+%28x+-+1000%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "multiply both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=100%2A%28x+-+1000%29 ALIGN=MIDDLE  ALT=\"100%2A%28x+-+1000%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3%2A%28x+-+1000%29+=+%28y+-+39%29%2A100 ALIGN=MIDDLE  ALT=\"3%2A%28x+-+1000%29+=+%28y+-+39%29%2A100\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3x+-+3000+=+100y+-+3900 ALIGN=MIDDLE  ALT=\"3x+-+3000+=+100y+-+3900\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=100y+=+3x+%2B+900 ALIGN=MIDDLE  ALT=\"100y+=+3x+%2B+900\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+%283%2F100%29x+%2B+9 ALIGN=MIDDLE  ALT=\"y+=+%283%2F100%29x+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" > or in this case,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C+=+%283%2F100%29n+%2B+9 ALIGN=MIDDLE  ALT=\"C+=+%283%2F100%29n+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" > answer<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "See if this line goes through (1000, 39) and (3000,99)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C+=+%283%2F100%29n+%2B+9 ALIGN=MIDDLE  ALT=\"C+=+%283%2F100%29n+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=39+=+%283%2F100%29%2A1000+%2B+9 ALIGN=MIDDLE  ALT=\"39+=+%283%2F100%29%2A1000+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=39+=+30+%2B+9 ALIGN=MIDDLE  ALT=\"39+=+30+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=39+=+39 ALIGN=MIDDLE  ALT=\"39+=+39\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C+=+%283%2F100%29n+%2B+9 ALIGN=MIDDLE  ALT=\"C+=+%283%2F100%29n+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=99+=+%283%2F100%293000+%2B+9 ALIGN=MIDDLE  ALT=\"99+=+%283%2F100%293000+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=99+=+90+%2B+9 ALIGN=MIDDLE  ALT=\"99+=+90+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=99+=+99 ALIGN=MIDDLE  ALT=\"99+=+99\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK<BR>\n" );
document.write( "Find the cost of 2400 cubic feet of natural gas.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C+=+%283%2F100%29n+%2B+9 ALIGN=MIDDLE  ALT=\"C+=+%283%2F100%29n+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C+=+%283%2F100%292400+%2B+9 ALIGN=MIDDLE  ALT=\"C+=+%283%2F100%292400+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C+=+72+%2B+9 ALIGN=MIDDLE  ALT=\"C+=+72+%2B+9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C+=+81 ALIGN=MIDDLE  ALT=\"C+=+81\"   DISABLED_style= \"max-width:90%; height:auto;\" > dollars answer </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );