document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=202736>Question 202736</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I'm trying to determine a quadratic equation that exhibits such:<BR>\n" );
document.write( "The equation I am working with is the expected number of ticket sales for each day where x=1.<BR>\n" );
document.write( "Tickets = -0.2x2 + 12x + 11<BR>\n" );
document.write( "I need to find a quadratic equation to determine the last day that tickets will be sold.  (Note:  Write your answer in terms of the number of days after ticket sales begin.)\r<BR>\n" );
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document.write( "I have tried: -0.2x2 + 12x + 11 = t (representing number of tickets)\r<BR>\n" );
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document.write( "Should I find t first and then substitute t to find x (number of days)? Or should I have the equation equal 0? (-0.2x2 + 12x + 11) = 0\r<BR>\n" );
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document.write( "I would really appreciate your help with this problem.  \r<BR>\n" );
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document.write( "Thank you<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #152934 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=152934\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I'm trying to determine a quadratic equation that exhibits such:<BR>\n" );
document.write( "The equation I am working with is the expected number of ticket sales for each day where x=1.<BR>\n" );
document.write( "Tickets = -0.2x2 + 12x + 11<BR>\n" );
document.write( "I need to find a quadratic equation to determine the last day that tickets will be sold. (Note: Write your answer in terms of the number of days after ticket sales begin.) <BR>\n" );
document.write( "I have tried: -0.2x^2 + 12x + 11 = t (representing number of tickets) <BR>\n" );
document.write( "Should I find t first and then substitute t to find x (number of days)? Or should I have the equation equal 0? (-0.2x^2 + 12x + 11) = 0 <BR>\n" );
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document.write( "I think you want to solve -0.2x^2 + 12x + 11 > 0<BR>\n" );
document.write( "That will tell you for what values the number of tickes sold is positive.<BR>\n" );
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document.write( "So solve -0.2x^2 + 12x + 11 = 0<BR>\n" );
document.write( "x = [-12 +- sqrt(144 - 4*-0.2*11)]/(2*-0.2)<BR>\n" );
document.write( "x = [-12 +- sqrt(152.8)]/(-0.4)<BR>\n" );
document.write( "x = [-12+-12.36]/(-.4)<BR>\n" );
document.write( "x = 0.36/-0.4 = -0.9<BR>\n" );
document.write( "OR<BR>\n" );
document.write( "x = (-12-12.36)/(-.4)<BR>\n" );
document.write( "x = 60.9<BR>\n" );
document.write( "-------------------<BR>\n" );
document.write( "So the quadratic is positive for -0.9 < x < 60.9 <BR>\n" );
document.write( "The last day tickets are sold is day # 60<BR>\n" );
document.write( "The 1st day tickets are sold is day # 0<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );