document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=174462>Question 174462</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0618595554/algebrahomeworkh>Algebra 2, Texas Edition</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> A car wash charges a flat rate for the first 8 minutes of washing time and also charges a certain amount for each additional minute of washing time.  Gina took 12 minutes to wash her car and it cost her a total of $5.00.  Kris took 17 minutes to was his truck at a total cost of $6.25.  Write an equation that models the total cost of a car wash as a function of the number of minutes spent washing a vehicle to find the slope of a line parallel to the line. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #129470 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=129470\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A car wash charges a flat rate for the first 8 minutes of washing time and also charges a certain amount for each additional minute of washing time. Gina took 12 minutes to wash her car and it cost her a total of $5.00. Kris took 17 minutes to was his truck at a total cost of $6.25. Write an equation that models the total cost of a car wash as a function of the number of minutes spent washing a vehicle to find the slope of a line parallel to the line.<BR>\n" );
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document.write( "This problem came up recently, except the phrase,\"slope of a line parallel to the line\" which I am not sure how this applies to this problem.<BR>\n" );
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document.write( "Let a = cost per minute<BR>\n" );
document.write( "Let b = flat rate for the 1st 8 minutes<BR>\n" );
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document.write( "Find a & b using the two equations<BR>\n" );
document.write( "G's cost<BR>\n" );
document.write( "a(12-8) + b = 5<BR>\n" );
document.write( "4a + b = 5<BR>\n" );
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document.write( "K's cost<BR>\n" );
document.write( "a(17-8) + b = 6.25<BR>\n" );
document.write( "9a + b = 6.25<BR>\n" );
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document.write( "Use elimination, subtract G's equation from K's equation:<BR>\n" );
document.write( "9a + b = 6.25<BR>\n" );
document.write( "4a + b = 5.00<BR>\n" );
document.write( "-----------------subtraction eliminates b, find a<BR>\n" );
document.write( "5a = 1.25<BR>\n" );
document.write( "a = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1.25%2F5 ALIGN=MIDDLE  ALT=\"1.25%2F5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "a = .25 per minute<BR>\n" );
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document.write( "Find b:<BR>\n" );
document.write( "4(.25) + b = 5<BR>\n" );
document.write( "b = 5 - 1<BR>\n" );
document.write( "b = $4, cost for 1st 8 minutes<BR>\n" );
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document.write( "Check solutions in the K's equation:<BR>\n" );
document.write( "9(.25) + 4 = 6.25<BR>\n" );
document.write( "2.25 + 4 = 6.25<BR>\n" );
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document.write( "\"Write an equation that models the total cost of a car wash as a function as the number of minutes spent washing a vehicle and find the flat rate for the first 8 minutes.\"<BR>\n" );
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document.write( "let m = no. of minutes to wash the vehicle<BR>\n" );
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document.write( "C(m) = .25(m-8) + 4 </SPAN>\n" );
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