document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=565987>Question 565987</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I have to create a demand equation.  My problem is to suppose that a market research company finds that at a price of p=$20, they would sell x=42 tiles each month.  If they lower the price to p=$10, then more people would purchase the tile, and they can expect to sell x=52 tiles in a month's time.  Find the equation of the line for the demand equation.\r<BR>\n" );
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document.write( "I know my answer needs to be written in the form p=mx+b and I know my equation needs two points in the form (x,p).  I know I need to plug in my information from the above problem using the x values of $10 and $20 and I need to use my tiles of 42 and 52, but I cannot figure out how to structure the problem showing all my work.\r<BR>\n" );
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document.write( "Thank you for your help.<BR>\n" );
document.write( "Lindsay </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #366083 by </B><A HREF=/tutors/aboutme.mpl?userid=htmentor><B>htmentor(1343)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=htmentor><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=htmentor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=366083\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I have to create a demand equation.  My problem is to suppose that a market research company finds that at a price of p=$20, they would sell x=42 tiles each month.  If they lower the price to p=$10, then more people would purchase the tile, and they can expect to sell x=52 tiles in a month's time.  Find the equation of the line for the demand equation.\r<BR>\n" );
document.write( "\n" );
document.write( "I know my answer needs to be written in the form p=mx+b and I know my equation needs two points in the form (x,p).  I know I need to plug in my information from the above problem using the x values of $10 and $20 and I need to use my tiles of 42 and 52, but I cannot figure out how to structure the problem showing all my work.<BR>\n" );
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document.write( "The equation is of the form p = mx + b<BR>\n" );
document.write( "We can use the given information to obtain 2 equations in 2 unknowns:<BR>\n" );
document.write( "Given: p=20 when x=42 20 = 42m + b<BR>\n" );
document.write( "Given: p=10 when x=52 10 = 52m + b<BR>\n" );
document.write( "Subtract the 2nd equation from the 1st:<BR>\n" );
document.write( "10 = -10m<BR>\n" );
document.write( "m = -1<BR>\n" );
document.write( "Now substitute this value into one of the two equations above<BR>\n" );
document.write( "10 = -52 + b -> b = 62<BR>\n" );
document.write( "So the equation is p = -x + 62 </SPAN>\n" );
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