document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1106268>Question 1106268</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How would I find the equation of a parabola whose vertex is (0,0) and two other points are (1,-2) and (-1,-2)? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #721209 by </B><A HREF=/tutors/aboutme.mpl?userid=math_helper><B>math_helper(2461)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=math_helper><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=math_helper><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=721209\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <BR>\n" );
document.write( "The vertex form of a parabola is  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+y+=+a%28x-h%29%5E2+-+k+ ALIGN=MIDDLE  ALT=\"+y+=+a%28x-h%29%5E2+-+k+\"   DISABLED_style= \"max-width:90%; height:auto;\" > where (h,k) = coordinates of the vertex\r<BR>\n" );
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document.write( "The vertex is given to be at (0,0), simplifying the above to <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+y+=+ax%5E2+ ALIGN=MIDDLE  ALT=\"+y+=+ax%5E2+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Picking one of the other two points (1,-2) allows us to find a:  <BR>\n" );
document.write( "                  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=++-2+=+a%2A%281%29%5E2+ ALIGN=MIDDLE  ALT=\"++-2+=+a%2A%281%29%5E2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "                  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+-2+ ALIGN=MIDDLE  ALT=\"+a+=+-2+\"   DISABLED_style= \"max-width:90%; height:auto;\" >     —>   <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+highlight%28y+=+-2x%5E2+%29+ ALIGN=MIDDLE  ALT=\"+highlight%28y+=+-2x%5E2+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Since a<0, the parabola opens downward </SPAN>\n" );
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