document.write( "Question 929710: find the quadratic function y = ax ^ 2 + bx + c whose graph passes through the given points.\r
\n" ); document.write( "\n" ); document.write( "(1,-1)(-1,-9)(-2,-10)\r
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\n" ); document.write( "\n" ); document.write( "thanks in advance for the help!
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Algebra.Com's Answer #564440 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
to find the quadratic function \"y+=+ax+%5E+2+%2B+bx+%2B+c\" whose graph passes through the given points (\"1\",\"-1\")(\"-1\",\"-9\")(\"-2\",\"-10\"), we need to find \"a\",\"b\",and \"a\" and we can do it using given points\r
\n" ); document.write( "\n" ); document.write( "\"y+=+ax+%5E+2+%2B+bx+%2B+c\" ...plug in \"x=1\" and \"y=-1\" from (\"1\",\"-1\")\r
\n" ); document.write( "\n" ); document.write( "\"-1+=+a%2A1+%5E+2+%2B+b%2A1+%2B+c\"\r
\n" ); document.write( "\n" ); document.write( "\"-1+=+a+%2B+b+%2B+c\".........eq.1\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+ax+%5E+2+%2B+bx+%2B+c\" ...plug in \"x=-1\" and \"y=-9\" from (\"-1\",\"-9\")\r
\n" ); document.write( "\n" ); document.write( "\"-9=+a%28-1%29%5E2+%2Bb%28-1%29+%2B+c\"\r
\n" ); document.write( "\n" ); document.write( "\"-9=+a+-b+%2B+c\".........eq.2\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+ax+%5E+2+%2B+bx+%2B+c\" ...plug in \"x=-2\" and \"y=-10\" from (\"-2\",\"-10\")\r
\n" ); document.write( "\n" ); document.write( "\"-10=+a%28-2%29+%5E+2+%2B+b%28-2%29+%2B+c\"\r
\n" ); document.write( "\n" ); document.write( "\"-10=+4a+-2b+%2B+c\"..........eq.3\r
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\n" ); document.write( "\n" ); document.write( "you have a system:\r
\n" ); document.write( "\n" ); document.write( "\"-1+=+a+%2B+b+%2B+c\".........eq.1
\n" ); document.write( "\"-9=+a+-b+%2B+c\".........eq.2
\n" ); document.write( "\"-10=+4a+-2b+%2B+c\"..........eq.3
\n" ); document.write( "_______________________________\r
\n" ); document.write( "\n" ); document.write( "start with\r
\n" ); document.write( "\n" ); document.write( "\"-1+=+a+%2B+b+%2B+c\".........eq.1
\n" ); document.write( "\"-9=+a+-b+%2B+c\".........eq.2
\n" ); document.write( "___________________________subtract 2 from 1\r
\n" ); document.write( "\n" ); document.write( "\"-1-%28-9%29+=+a-a+%2B+b-%28-b%29+%2B+c-c\"\r
\n" ); document.write( "\n" ); document.write( "\"-1%2B9+=+cross%28a%29-cross%28a%29+%2B+b%2Bb+%2B+cross%28c%29-cross%28c%29\"\r
\n" ); document.write( "\n" ); document.write( "\"8+=+2b\"\r
\n" ); document.write( "\n" ); document.write( "\"8%2F2+=+b\"\r
\n" ); document.write( "\n" ); document.write( "\"highlight%28b=4%29\"\r
\n" ); document.write( "\n" ); document.write( "go to \"-10=+4a+-2b+%2B+c\"..........eq.3, plug in \"b\"\r
\n" ); document.write( "\n" ); document.write( "\"-10=+4a+-2%2A4+%2B+c\"\r
\n" ); document.write( "\n" ); document.write( "\"-10=+4a+-8+%2B+c\"\r
\n" ); document.write( "\n" ); document.write( "\"-10%2B8=+4a%2B+c\"\r
\n" ); document.write( "\n" ); document.write( "\"-2=+4a%2B+c\"\r
\n" ); document.write( "\n" ); document.write( "\"-2-4a=c\"\r
\n" ); document.write( "\n" ); document.write( "\"c=-2-4a\"\r
\n" ); document.write( "\n" ); document.write( "go to \"-1+=+a+%2B+b+%2B+c\".........eq.1 substitute \"b\" and \"c\"\r
\n" ); document.write( "\n" ); document.write( "\"-1+=+a+%2B+4+-2-4a\"\r
\n" ); document.write( "\n" ); document.write( "\"-1+=+2+-3a\"\r
\n" ); document.write( "\n" ); document.write( "\"3a+=2%2B1\"\r
\n" ); document.write( "\n" ); document.write( "\"3a+=+3\"\r
\n" ); document.write( "\n" ); document.write( "\"highlight%28a+=1%29\"\r
\n" ); document.write( "\n" ); document.write( "go to \"c=-2-4a\" plug in \"a\" and find \"c\"\r
\n" ); document.write( "\n" ); document.write( "\"c=-2-4%281%29\"\r
\n" ); document.write( "\n" ); document.write( "\"c=-2-4\"\r
\n" ); document.write( "\n" ); document.write( "\"highlight%28c=-6%29\"\r
\n" ); document.write( "\n" ); document.write( "so, your equation is: \"y+=+x+%5E+2+%2B+4x+-6\"\r
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\n" ); document.write( "\n" ); document.write( "(1,-1)(-1,-9)(-2,-10)
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