document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=466765>Question 466765</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me solve:  The number of tickets sold for a Broadway musical is given by N(x)= -0.4x^2 + 12x + 12 where \"x\" is the number of days since the concert was first announced. When will daily tickets sales peak and how many tickets will be sold that day?\r<BR>\n" );
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document.write( "N(x)= -0.4x^2 + 12x + 12 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #320041 by </B><A HREF=/tutors/aboutme.mpl?userid=ccs2011><B>ccs2011(207)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ccs2011><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=ccs2011><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=320041\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Since this is a quadratic function, its graph is parabolic.<BR>\n" );
document.write( "The leading coefficient(-0.4) is negative, this tells us its a downward pointing parabola.<BR>\n" );
document.write( "The vertex of this parabola will give us the maximum value of N(x) or the highest daily ticket sales and the day it occurred.<BR>\n" );
document.write( "To find vertex, first find line of symmetry or x_coordinate of vertex.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-b%29%2F2a ALIGN=MIDDLE  ALT=\"x+=+%28-b%29%2F2a\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "where<BR>\n" );
document.write( "a = -0.4<BR>\n" );
document.write( "b = 12<BR>\n" );
document.write( "c = 12<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-12%29%2F2%28-0.4%29 ALIGN=MIDDLE  ALT=\"x+=+%28-12%29%2F2%28-0.4%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+15 ALIGN=MIDDLE  ALT=\"x+=+15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Substitute this value into function<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-0.4%2815%5E2%29+%2B+12%2815%29+%2B+12 ALIGN=MIDDLE  ALT=\"y+=+-0.4%2815%5E2%29+%2B+12%2815%29+%2B+12\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-90+%2B+180+%2B+12 ALIGN=MIDDLE  ALT=\"y+=+-90+%2B+180+%2B+12\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+102 ALIGN=MIDDLE  ALT=\"y+=+102\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Vertex: (15,102)<BR>\n" );
document.write( "Thus, on the 15th day ticket sales peaked at 102 tickets sold. </SPAN>\n" );
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