document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=354010>Question 354010</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find an equation of the fom y=ax^2+b whose graph passes through the points (-1,1) and (2,7).<BR>\n" );
document.write( "   Please help. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #253038 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=253038\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find an equation of the fom y=ax^2+b whose graph <BR>\n" );
document.write( "passes through the points (-1,1) and (2,7).<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Substitute each x/y pair into the equation so<BR>\n" );
document.write( "you can solve for \"a\" and for \"b\".<BR>\n" );
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document.write( "1 = a + b<BR>\n" );
document.write( "7 = 4a+b<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "Subtract the 1st from the 2nd and solve for \"a\":<BR>\n" );
document.write( "6 = 3a<BR>\n" );
document.write( "a = 2<BR>\n" );
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document.write( "Since 1 = a+b, b = 1-2 = -1<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Equation:<BR>\n" );
document.write( "y = 2x^2-1<BR>\n" );
document.write( "===================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );