document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=609287>Question 609287</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Alright so I have to do quadratic FUNCTIONS, not quadratic equations. Apparently there is a difference so I have to solve all these other little problems to get the ax^2+bx+c. For example, (not word to word but you'll get the point): Find c(x)=? it takes $103 to make 3 cameras, $163 to make 7 cameras and $328 to make 12 cameras. ok, i know how to but them into the three equations: 103=6a+3b+c, 163=49a+7b+c, and 328=144a+7b+c. but after that i'm totally lost.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #384154 by </B><A HREF=/tutors/aboutme.mpl?userid=SwiftAlbatross><B>SwiftAlbatross(13)</B></A><img src=\"/images/stars/stars-06.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=SwiftAlbatross><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=SwiftAlbatross><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=384154\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 103 = 9a + 3b + c<BR>\n" );
document.write( "163 = 49a + 7b + c<BR>\n" );
document.write( "328 = 144a + 12b + c\r<BR>\n" );
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document.write( "Solve for c:<BR>\n" );
document.write( "103 = 9a + 3b + c<BR>\n" );
document.write( "c = 103 - 9a - 3b\r<BR>\n" );
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document.write( "Plug c into other equations:<BR>\n" );
document.write( "163 = 49a + 7b + 103 - 9a - 3b<BR>\n" );
document.write( "Combine like terms:<BR>\n" );
document.write( "60 = 40a + 4b<BR>\n" );
document.write( "328 = 144a + 12b + 103 - 9a - 3b<BR>\n" );
document.write( "225 = 135a + 9b\r<BR>\n" );
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document.write( "Work with these two equations:<BR>\n" );
document.write( "60 = 40a + 4b<BR>\n" );
document.write( "225 = 135a + 9b\r<BR>\n" );
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document.write( "Solve for b: <BR>\n" );
document.write( "60 = 40a + 4b<BR>\n" );
document.write( "*2     *2<BR>\n" );
document.write( "120 = 80a + 8b\r<BR>\n" );
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document.write( "225 = 135a + 9b<BR>\n" );
document.write( "- 120 = - 80a - 8b<BR>\n" );
document.write( "105 = 55a + b<BR>\n" );
document.write( "b = 105 - 55a\r<BR>\n" );
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document.write( "Substitute b into one of equations:<BR>\n" );
document.write( "60 = 40a + 4b<BR>\n" );
document.write( "60 = 40a + 4(105 - 55a)<BR>\n" );
document.write( "60 = 40a + 420 - 220a<BR>\n" );
document.write( "-360 = -180a<BR>\n" );
document.write( "a = 2\r<BR>\n" );
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document.write( "Substitue a into equation:<BR>\n" );
document.write( "60 = 40a + 4b<BR>\n" );
document.write( "60 = 40(2) + 4b<BR>\n" );
document.write( "60 = 80 + 4b<BR>\n" );
document.write( "-20 = 4b<BR>\n" );
document.write( "b = -5\r<BR>\n" );
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document.write( "Substitute a and b into one of the first equations:<BR>\n" );
document.write( "103 = 9a + 3b + c<BR>\n" );
document.write( "103 = 9(2) + 3(-5) + c<BR>\n" );
document.write( "103 = 18 - 15 + c<BR>\n" );
document.write( "103 = 3 + c<BR>\n" );
document.write( "c = 100\r<BR>\n" );
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document.write( "Check with other 2 equations.<BR>\n" );
document.write( "So the quadratic function is <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+Camera%28x%29+=+2x%5E2+-+5x+%2B+100+ ALIGN=MIDDLE  ALT=\"+Camera%28x%29+=+2x%5E2+-+5x+%2B+100+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );