document.write( "Question 1209407: If a+c=-8 and c-b=-4, find the value of $\"3a%5E2-6b%5E20%2B3c%5E2\"$ .\r
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Algebra.Com's Answer #848762 by ikleyn(52786) $\"\"$ $\"About$

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\n" ); document.write( "If a+c=-8 and c-b=-4, find the value of $\"3a%5E2-6b%5E20%2B3c%5E2\"$ .
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\n" ); document.write( "\n" ); document.write( "      My interior voice tells me that the correct problem is THIS\r
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\n" ); document.write( "\n" ); document.write( "                If   a + c = -8   and   c - b = -4,   find the value of    $\"3a%5E2-6b%5E2%2B3c%5E2\"$ .         (*)\r
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\n" ); document.write( "\n" ); document.write( "        I will solve in this formulation\r
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document.write( "We have \r\n" );
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document.write( "    a + c = -8,    (1)\r\n" );
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document.write( "    c - b = -4.    (2)\r\n" );
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document.write( "Subtract eq(2) from eq(1).  You will get\r\n" );
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document.write( "    a + b = -4     (3)\r\n" );
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document.write( "Now \r\n" );
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document.write( "     =  = (3*(a-b)*(a+b)-(b-c)*(b+c)) = \r\n" );
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document.write( "            here replace  (a+b)  by -4 based on (3);  replace  (b-c) by 4  based on (2),  and continue\r\n" );
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document.write( "    = 3*((a-b)*(-4) - 4*(b+c)) = 3*4(b-a)-(b+c)) = 12*(-a-c) = \r\n" );
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document.write( "            here replace (-a-c)  by 8,  based on (1),  and continue\r\n" );
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document.write( "    = 12*8 = 96.\r\n" );
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document.write( "ANSWER.  After simplifications, the value of  (*)  is  96.\r\n" );
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