document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=522737>Question 522737</A>: <I><SPAN STYLE=\"word-break: break-all;\"> how do i find the equation of the parabola, y=ax^2+bx+c, that passes through the following three points : (-2,40),(1,7),(3,15)? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #346971 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=346971\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> how do i find the equation of the parabola, y=ax^2+bx+c, that passes through the following three points : (-2,40),(1,7),(3,15)?<BR>\n" );
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document.write( "Substitute those value for x and y.<BR>\n" );
document.write( "The solve the tree equations for a,b,c.<BR>\n" );
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document.write( "ax^2  +  bx  + c  =  y<BR>\n" );
document.write( "a(4)  +  b(-2)+c  = 40<BR>\n" );
document.write( "a(1)  +  b(1) +c  =  7<BR>\n" );
document.write( "a(9)  +  b(3) +c  =  15<BR>\n" );
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document.write( "I used a matrix method to solve the 3 equations and got:<BR>\n" );
document.write( "a = 3 <BR>\n" );
document.write( "b = -8<BR>\n" );
document.write( "c = 12<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Equation:<BR>\n" );
document.write( "y = 3x^2-8x+12<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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