document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=428552>Question 428552</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hi need some help with this one:\r<BR>\n" );
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document.write( "Find the vertex, graph and find the x-intercepts of the parabola:\r<BR>\n" );
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document.write( "y=-x^2+4x\r<BR>\n" );
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document.write( "Thanks! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #297845 by </B><A HREF=/tutors/aboutme.mpl?userid=Gogonati><B>Gogonati(855)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Gogonati><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=Gogonati><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=297845\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Solution:Since the coefficient beside <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%5E2 ALIGN=MIDDLE  ALT=\"x%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" >, is negative we have a downward parabola.<BR>\n" );
document.write( "To find x-intercepts we solve the equation:<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-x%5E2%2B4x=0 ALIGN=MIDDLE  ALT=\"-x%5E2%2B4x=0\"   DISABLED_style= \"max-width:90%; height:auto;\" > => x(4-x)=0 => x=0 and x=4<BR>\n" );
document.write( "Therefore the x-intercepts are:(0,0) and (4,0)\r<BR>\n" );
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document.write( "The vertex of parabola is the point (-b/2a, f(-b/2a),substitute:\r<BR>\n" );
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document.write( "x=-4/-2=2 and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y=-%282%29%5E2%2B4%2A2 ALIGN=MIDDLE  ALT=\"y=-%282%29%5E2%2B4%2A2\"   DISABLED_style= \"max-width:90%; height:auto;\" >, y=4 Thus the vertex is: (2,4)\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28300%2C+300%2C+-5%2C+5%2C+-5%2C+5%2C+-x%5E2%2B4x%29 ALIGN=MIDDLE  ALT=\"graph%28300%2C+300%2C+-5%2C+5%2C+-5%2C+5%2C+-x%5E2%2B4x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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