document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=486965>Question 486965</A>: <I><SPAN STYLE=\"word-break: break-all;\"> f(x)=-4x^2+20x\r<BR>\n" );
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document.write( "Use the vertex formula to find the vertex. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #332877 by </B><A HREF=/tutors/aboutme.mpl?userid=John10><B>John10(297)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=John10><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=John10><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=332877\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Apply the vertex formula: V = (-b/2a , f(-b/2a))<BR>\n" );
document.write( "x = -b/2a = -20/2(-4) = -20/-8 = 5/2<BR>\n" );
document.write( "y = f(5/2)= -4(5/2)^2 + 20(5/2) = -4(25/4) + 50 = -25 + 50 = 25<BR>\n" );
document.write( "Thus the vertex is (5/2, 25)<BR>\n" );
document.write( "John10:) </SPAN>\n" );
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