document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1138659>Question 1138659</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A cell phone company has the following cost and revenue functions:<BR>\n" );
document.write( "C(x) = 8x^2 − 600x + 21,500 and<BR>\n" );
document.write( "R(x) = −3x^2 + 480x<BR>\n" );
document.write( "What is the quantity range of cell phones they should produce each day so there is a profit? Round to the nearest numbers that generate profit.\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 #756458 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=756458\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Look at R(x)-C(x) for profit<BR>\n" );
document.write( "That is -3x^2+480x-(8x^2-600x+21500)=<BR>\n" );
document.write( "watch signs<BR>\n" );
document.write( "-11x^2+1080x-21500>0, to generate a profit.<BR>\n" );
document.write( "The maximum is at x=-b/2a=-1080/-22=49.09<BR>\n" );
document.write( "the zero point is found using the quadratic formula.  The discriminant b^2-4ac is 220400, and its square root is 469.47<BR>\n" );
document.write( "x=(-1080+/-469.47)/-22, so one root: (-1080-469.47/-22)=70.43 or 70 and the other is -1080+469.47/-22=27.75 or 28<BR>\n" );
document.write( "The numbers are between 28 and 70 inclusive. ANSWER<BR>\n" );
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