document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=997636>Question 997636</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose a certain outlet chain selling appliances has found that for one brand of stereo system, the monthly demand is 210 when the price is $700. However, when the price is $625, the monthly demand is 255. Assuming that the demand function for this system is linear, write the equation for the demand function. Use p for price and q for quantity. \r<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 #615647 by </B><A HREF=/tutors/aboutme.mpl?userid=addingup><B>addingup(3677)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=addingup><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=addingup><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=615647\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Demand function: <BR>\n" );
document.write( "P= D(q)where p is the price and q is the quantity in demand.<BR>\n" );
document.write( "We know that if the price is 700 the demand is 210 and if the price is 625 the demand is 255.<BR>\n" );
document.write( "To solve this problem, we first need to create the demand function <BR>\n" );
document.write( "p = D(q)<BR>\n" );
document.write( "and then use it to find the revenue function <BR>\n" );
document.write( "R(q)<BR>\n" );
document.write( "Now, I may have already given you the answer that you need if all you need is the equation p= D(q). But if you actually have to find the demand function, things get a little more complicated.<BR>\n" );
document.write( "Since the demand function is linear, we know that it can be written in slope-intercept form as  <BR>\n" );
document.write( "p= mx + b<BR>\n" );
document.write( "This formula will give you a linear slope showing what happens to q as price goes either up or down. Note that we can write the information you already have in ordered pairs that you can graph: (2.10, 7)(2.55, 6.25). I divided all numbers by 100 to make it easier to graph. You can graph it yourself or go to one of the free online graphing sites  \r<BR>\n" );
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