document.write( "Question 959876: The curve y=ax˛+bx+c passes (2,5), (3,12) and (-1,-4). Find the equation of the curve. \n" ); document.write( "
Algebra.Com's Answer #586664 by MathLover1(20849)\"\" \"About 
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\n" ); document.write( "\"y=ax%5E2%2Bbx%2Bc\" passes (\"2\",\"5\"), (\"3\",\"12\") and (\"-1\",\"-4\")\r
\n" ); document.write( "\n" ); document.write( "use given points, set the system of three equations, solve it for \"a\",\"b\", and \"c\"\r
\n" ); document.write( "\n" ); document.write( "\"y=ax%5E2%2Bbx%2Bc\".....for (\"2\",\"5\")\r
\n" ); document.write( "\n" ); document.write( "\"5=a%2A2%5E2%2Bb%2A2%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"5=4a%2B2b%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"4a%2B2b%2Bc-5=0\"..............eq.1\r
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\n" ); document.write( "\n" ); document.write( "\"y=ax%5E2%2Bbx%2Bc\".....for (\"3\",\"12\")\r
\n" ); document.write( "\n" ); document.write( "\"12=a%2A3%5E2%2Bb%2A3%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"12=9a%2B3b%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"9a%2B3b%2Bc-12=0\"..............eq.2\r
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\n" ); document.write( "\n" ); document.write( "\"y=ax%5E2%2Bbx%2Bc\".....for (\"-1\",\"-4\")\r
\n" ); document.write( "\n" ); document.write( "\"-4=a%2A%28-1%29%5E2%2Bb%2A%28-1%29%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"-4=a-b%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"a-b%2Bc%2B4=0\"..............eq.3\r
\n" ); document.write( "\n" ); document.write( "so, your system is:\r
\n" ); document.write( "\n" ); document.write( "\"4a%2B2b%2Bc-5=0\"..............eq.1
\n" ); document.write( "\"9a%2B3b%2Bc-12=0\"..............eq.2
\n" ); document.write( "\"a-b%2Bc%2B4=0\"..............eq.3
\n" ); document.write( "---------------------------------
\n" ); document.write( "subtract eq.1 from eq.2\r
\n" ); document.write( "\n" ); document.write( "\"9a%2B3b%2Bc-12-%284a%2B2b%2Bc-5%29=0\"\r
\n" ); document.write( "\n" ); document.write( "\"9a%2B3b%2Bc-12-4a-2b-c%2B5=0\"\r
\n" ); document.write( "\n" ); document.write( "\"5a%2Bb-7=0\"......solve for \"b\"\r
\n" ); document.write( "\n" ); document.write( "\"b=7-5a\".........substitute in eq.3\r
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\n" ); document.write( "\n" ); document.write( "\"a-%287-5a%29%2Bc%2B4=0\"..............eq.3\r
\n" ); document.write( "\n" ); document.write( "\"a-7%2B5a%2Bc%2B4=0\"\r
\n" ); document.write( "\n" ); document.write( "\"6a-3%2Bc=0\".........solve for \"c\"\r
\n" ); document.write( "\n" ); document.write( "\"c=3-6a\"\r
\n" ); document.write( "\n" ); document.write( "go to \"4a%2B2b%2Bc-5=0\"..............eq.1 substitute \"b\" and \"c\"\r
\n" ); document.write( "\n" ); document.write( "\"4a%2B2%287-5a%29%2B%283-6a%29-5=0\"...........solve for \"a\"\r
\n" ); document.write( "\n" ); document.write( "\"4a%2B14-10a%2B3-6a-5=0\"\r
\n" ); document.write( "\n" ); document.write( "\"12-12a=0\"\r
\n" ); document.write( "\n" ); document.write( "\"12=12a\"\r
\n" ); document.write( "\n" ); document.write( "\"highlight%28a=1%29\"\r
\n" ); document.write( "\n" ); document.write( "now find \"b\" and \"c\"\r
\n" ); document.write( "\n" ); document.write( "\"b=7-5a\"
\n" ); document.write( "\"b=7-5%2A1\"
\n" ); document.write( "\"highlight%28b=2%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"c=3-6a\"
\n" ); document.write( "\"c=3-6%2A1\"
\n" ); document.write( "\"highlight%28c=-3%29\"\r
\n" ); document.write( "\n" ); document.write( "so, your equation is: \"y=x%5E2%2B2x-3\"\r
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