document.write( "Question 374855: Algebrically, find the quadratic equation that passes through the points (-1, 0), (2,12),(-2,8) \n" ); document.write( "
Algebra.Com's Answer #266587 by Fombitz(32388)\"\" \"About 
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The general equation for a quadratic is, \"y=ax%5E2%2Bbx%2Bc\"
\n" ); document.write( "\"0=a%28-1%29%5E2%2Bb%28-1%29%2Bc\"
\n" ); document.write( "1.\"a-b%2Bc=0\"
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\n" ); document.write( "\"12=a%282%29%5E2%2Bb%282%29%2Bc\"
\n" ); document.write( "2.\"4a%2B2b%2Bc=12\"
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\n" ); document.write( "\"8=a%28-2%29%5E2%2Bb%28-2%29%2Bc\"
\n" ); document.write( "3.\"4a-2b%2Bc=8\"
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\n" ); document.write( "Subtract eq. 1 from eq. 2,
\n" ); document.write( "\"4a%2B2b%2Bc-a%2Bb-c=12-0\"
\n" ); document.write( "\"3a%2B3b=12\"
\n" ); document.write( "4.\"a%2Bb=4\"
\n" ); document.write( "Subtract eq. 1 from eq. 3,
\n" ); document.write( "\"4a-2b%2Bc-a%2Bb-c=8-0\"
\n" ); document.write( "5.\"3a-b=8\"
\n" ); document.write( "Add eq. 4 and eq 5 together,
\n" ); document.write( "\"a%2Bb%2B3a-b=4%2B8\"
\n" ); document.write( "\"4a=12\"
\n" ); document.write( "\"a=3\"
\n" ); document.write( "Then from eq. 4,
\n" ); document.write( "\"3%2Bb=4\"
\n" ); document.write( "\"b=1\"
\n" ); document.write( "Then from eq. 1,
\n" ); document.write( "\"3-1%2Bc=0\"
\n" ); document.write( "\"c=-2\"
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\n" ); document.write( "\"highlight%28f%28x%29=3x%5E2%2Bx-2%29\"
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