document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=32405>Question 32405</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The number of mosquitoes m(x) in millions, in a certain area depends on the june rainfall x, in inches. m(x)-20x-x^2. What rainfall produces the max number of mosquitoes? 400, 10,0,20 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #18904 by </B><A HREF=/tutors/aboutme.mpl?userid=mukhopadhyay><B>mukhopadhyay(490)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mukhopadhyay><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=18904\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> m(x)= 20x-x^2 <BR>\n" );
document.write( "m(x) represents a parabola, opens downward (because of negative sign in x^2)<BR>\n" );
document.write( "The maximum will be attained at its vertex.<BR>\n" );
document.write( "x-coordinate of the vertex of a parabola ax^2 + bx + c is -b/2a<BR>\n" );
document.write( "-b/2a = -20/(-2 ) = 10<BR>\n" );
document.write( "Answer: 10<BR>\n" );
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