document.write( "Question 1199499: If $\"a-b=-6\"$ and $\"b%2Bc=9\"$ , find the value of $\"3a%5E2-b%5E2-2c%5E2\"$ . \n" ); document.write( "

Algebra.Com's Answer #833421 by ikleyn(52800) $\"\"$ $\"About$

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\n" ); document.write( "If a-b = -6 and b+c = 9, find the value of $\"3a%5E2-b%5E2-2c%5E2\"$ .
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document.write( "Then a = -6 + b,  c = 9 - b,\r\n" );
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document.write( "      3a^2 - b^2 - 2c^2 = 3*(-6+b)^2 - b^2 - 2*(9-b)^2 = \r\n" );
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document.write( "    = 3*(36 - 12b + b^2) - b^2 - 2*(81 - 18b + b^2) = 108 - 36b + 3b^2 - b^2 - 162 + 36b - 2b^2 =\r\n" );
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document.write( "    = combine like terms = -54. \r\n" );
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document.write( "ANSWER.  If a-b = -6  and  b+c = 9, then the value of  is -54.\r\n" );
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