document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=644067>Question 644067</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The monthly cost of driving a car depends on the number of miles driven. Lynn found that in May her driving cost was $350 for 420 mi and in June her cost was $470 for 900 mi. Assume that there is a linear relationship between the monthly cost C of driving a car and the distance driven d. <BR>\n" );
document.write( "(a) Find a linear equation that relates C and d. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #404785 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=404785\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The general form of the equation is<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+C+=+m%2Ad+%2B+b+ ALIGN=MIDDLE  ALT=\"+C+=+m%2Ad+%2B+b+\"   DISABLED_style= \"max-width:90%; height:auto;\" > where <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+m+ ALIGN=MIDDLE  ALT=\"+m+\"   DISABLED_style= \"max-width:90%; height:auto;\" > is the slope<BR>\n" );
document.write( "Plot <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+C+ ALIGN=MIDDLE  ALT=\"+C+\"   DISABLED_style= \"max-width:90%; height:auto;\" > on the vertical axis<BR>\n" );
document.write( "Plot <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+ ALIGN=MIDDLE  ALT=\"+d+\"   DISABLED_style= \"max-width:90%; height:auto;\" > on the horizontal<BR>\n" );
document.write( "Slope is ( change in C ) / ( change in d )<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+470+-+350+%29+%2F+%28+900+-+420+%29+ ALIGN=MIDDLE  ALT=\"+%28+470+-+350+%29+%2F+%28+900+-+420+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+120+%2F+480+=+1%2F4+ ALIGN=MIDDLE  ALT=\"+120+%2F+480+=+1%2F4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+m+=+1%2F4+ ALIGN=MIDDLE  ALT=\"+m+=+1%2F4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Now just plug in one of the 2 given points<BR>\n" );
document.write( "to find <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+ ALIGN=MIDDLE  ALT=\"+b+\"   DISABLED_style= \"max-width:90%; height:auto;\" >, the intercept on the vertical axis<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+470+=+%281%2F4%29%2A900+%2B+b+ ALIGN=MIDDLE  ALT=\"+470+=+%281%2F4%29%2A900+%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=+b+=+470+-+225+ ALIGN=MIDDLE  ALT=\"+b+=+470+-+225+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+245+ ALIGN=MIDDLE  ALT=\"+b+=+245+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "------------<BR>\n" );
document.write( "The equation is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+C+=+%281%2F4%29%2Ad+%2B+245+ ALIGN=MIDDLE  ALT=\"+C+=+%281%2F4%29%2Ad+%2B+245+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "check answer:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+350+=+%281%2F4%29%2A420+%2B+245+ ALIGN=MIDDLE  ALT=\"+350+=+%281%2F4%29%2A420+%2B+245+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+350+=+105+%2B+245+ ALIGN=MIDDLE  ALT=\"+350+=+105+%2B+245+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+350+=+350+ ALIGN=MIDDLE  ALT=\"+350+=+350+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Here's the plot:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+graph%28+400%2C+400%2C+-100%2C+1000%2C+-100%2C+500%2C+%281%2F4%29%2Ax+%2B+245+%29+ ALIGN=MIDDLE  ALT=\"+graph%28+400%2C+400%2C+-100%2C+1000%2C+-100%2C+500%2C+%281%2F4%29%2Ax+%2B+245+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );