document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=401658>Question 401658</A>: <I><SPAN STYLE=\"word-break: break-all;\"> find the equation of the parabola With the vertex on the y axis, axis of symmetry parallel to the x axis, and passes through (2, 2), (8,-1) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #284277 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=284277\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> find the equation of the parabola With the vertex on the y axis, axis of symmetry parallel to the x axis, and passes through (2, 2), (8,-1)<BR>\n" );
document.write( "----<BR>\n" );
document.write( "If vertex on y-axis it passes through (0,y)<BR>\n" );
document.write( "If axis of symmetry parallel to x-axis it passes thru <BR>\n" );
document.write( "---<BR>\n" );
document.write( "Form of equation: y = a(x-h)^2+k<BR>\n" );
document.write( "(0,y) implies y = a(x)^2+k<BR>\n" );
document.write( "(2,2) implies 2 = a(2)^2+k = 4a+k<BR>\n" );
document.write( "(8,-1) implies -1 = a(8)^2+k = 64a+k<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve the system:<BR>\n" );
document.write( "4a+k = 2<BR>\n" );
document.write( "64a+k = -1<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Subtract top from bottom to get:<BR>\n" );
document.write( "60a = -3<BR>\n" );
document.write( "a = -1/20<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve for \"k\":<BR>\n" );
document.write( "4a+k = 2<BR>\n" );
document.write( "4(-1/20) + k = 2<BR>\n" );
document.write( "(-1/5) + k = 2<BR>\n" );
document.write( "k = 11/5<BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "Equation:<BR>\n" );
document.write( "y = (-1/20)x^2 + (11/5)<BR>\n" );
document.write( "=============================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );