document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=485388>Question 485388</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the minimum or maximum point of the following parabola by using the completing square method.\r<BR>\n" );
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document.write( "f(x)=-x^2+10x-28\r<BR>\n" );
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document.write( "the following is my working..I am not sure whether it is correct..please advise..<BR>\n" );
document.write( "f(x)=-x^2+10x-28<BR>\n" );
document.write( "= -x^2 + 10x + (10/2 )^2  - (10/2 )^2  - 28<BR>\n" );
document.write( "= -(x+5)2 -53\r<BR>\n" );
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document.write( "From -(x+5)2 -53, compare with a(x-h)^2 +k<BR>\n" );
document.write( "h= -5, k= -53, since a <0, so it has a maximum point at (-5,-53).<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 #331973 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=331973\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find the minimum or maximum point of the following parabola by using the completing square method.\r<BR>\n" );
document.write( "\n" );
document.write( "f(x)=-x^2+10x-28\r<BR>\n" );
document.write( "\n" );
document.write( "the following is my working..I am not sure whether it is correct..please advise..<BR>\n" );
document.write( "f(x)=-x^2+10x-28<BR>\n" );
document.write( "= -x^2 + 10x + (10/2 )^2  - (10/2 )^2  - 28<BR>\n" );
document.write( "= -(x+5)2 -53\r<BR>\n" );
document.write( "\n" );
document.write( "From -(x+5)2 -53, compare with a(x-h)^2 +k<BR>\n" );
document.write( "h= -5, k= -53, since a <0, so it has a maximum point at (-5,-53).<BR>\n" );
document.write( "-------------------<BR>\n" );
document.write( "-x^2+10x-28 = 0<BR>\n" );
document.write( "-(x^2 -10x) = 28<BR>\n" );
document.write( "-(x^2 - 10x + 25) = 3 ( -25 is added to both sides)<BR>\n" );
document.write( "-(x-5)^2 - 3 = 0<BR>\n" );
document.write( "--> (5,-3)<BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "to check:<BR>\n" );
document.write( "Line of Symmetry is x = -b/2a<BR>\n" );
document.write( "x = -10/-2 = 5<BR>\n" );
document.write( "f(5) = -3<BR>\n" );
document.write( "--> (5,-3)<BR>\n" );
document.write( "-----------<BR>\n" );
document.write( "Completing the square is the worst method.  Avoid it if possible. </SPAN>\n" );
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