document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1013975>Question 1013975</A>: <I><SPAN STYLE=\"word-break: break-all;\"> So how would I go about solving this quadratic equation:\r<BR>\n" );
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document.write( "y=-1x^2 - 10x\r<BR>\n" );
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document.write( "I know the axis of symmetry is -5 because x=-b/2a. When I try to find the y axis however, I get y=25. Is that right? if not, how would I solve this question?  Thanks for helping me! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #630275 by </B><A HREF=/tutors/aboutme.mpl?userid=macston><B>macston(5194)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=macston><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=macston><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=630275\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> It depends on what you want to know.<BR>\n" );
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document.write( "y=-x^2-10x<BR>\n" );
document.write( "y=(-1x)(x+10)<BR>\n" );
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document.write( "To find the roots, let y=0<BR>\n" );
document.write( "(-1x)(x+10)=0<BR>\n" );
document.write( "-1x=0 --OR-- x+10=0<BR>\n" );
document.write( "x=0 --OR-- x=-10 <BR>\n" );
document.write( "Intercepts x axis at 0 and -10.<BR>\n" );
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document.write( "To find the x value at maximum(or minimum):<BR>\n" );
document.write( "Set first derivative=0<BR>\n" );
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document.write( "f(x)=-x^2-10x . (original equation)<BR>\n" );
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document.write( "f'(x)=-2x-10 . (first derivative)<BR>\n" );
document.write( "0=-2x-10<BR>\n" );
document.write( "10=-2x<BR>\n" );
document.write( "-5=x  <BR>\n" );
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document.write( "The sign of the second derivative tells if <BR>\n" );
document.write( "it has a maximum or minimum (if negative, <BR>\n" );
document.write( "it has maximum, if positive it has minimum)<BR>\n" );
document.write( "f''(x)=-2 . (second derivative)<BR>\n" );
document.write( "is negative, so there is a maximum where x=-5.<BR>\n" );
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document.write( "Find y where x=-5:<BR>\n" );
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document.write( "f(x)=-x^2-10x<BR>\n" );
document.write( "f(-5)=-(-5)^2-10(-5)=-25=50=25<BR>\n" );
document.write( "The maximum is at the point (-5,25), <BR>\n" );
document.write( "crosses x-axis at -10 and 0<BR>\n" );
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