document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1179261>Question 1179261</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Given the equation: Ax2 + Bx + C. When y is equal to 41, x is equal to -2. When y is<BR>\n" );
document.write( "equal to 20, x is equal to 5. When minimized, x is equal to 2. Find the sum of A and B. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #808789 by </B><A HREF=/tutors/aboutme.mpl?userid=htmentor><B>htmentor(1343)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=htmentor><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=htmentor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=808789\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> y = Ax^2 + Bx + C<BR>\n" );
document.write( "41 = A(-2)^2 + B(-2) + C<BR>\n" );
document.write( "20 = A(5)^2 + B(5) + C<BR>\n" );
document.write( "When minimized, dy/dx = 0 = 2Ax + B -> 2(2)A + B = 0 -> B = -4A<BR>\n" );
document.write( "Substitute in the 1st two equations:<BR>\n" );
document.write( "41 = 4A + 8A + C ->   41 = 12A + C<BR>\n" );
document.write( "20 = 25A - 20A + C -> 20 = 5A + C<BR>\n" );
document.write( "Subtract the 2nd from the 1st:<BR>\n" );
document.write( "21 = 7A -> A = 3<BR>\n" );
document.write( "Thus B = -12, and C = 41 - 12(3) -> C = 5 </SPAN>\n" );
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