document.write( "Question 830735: if a+b+c=4, then
\n" ); document.write( "a³+b³+c³-12c²+48c-64 is equal to
\n" ); document.write( "(A)3abc-12ab
\n" ); document.write( "(B)3abc+12ab
\n" ); document.write( "(C)abc+12ab
\n" ); document.write( "(D)3abc
\n" ); document.write( "please show how to solve this question \n" ); document.write( "
Algebra.Com's Answer #500837 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
if a+b+c=4, then
\n" ); document.write( "a³+b³+c³-12c²+48c-64 is equal to
\n" ); document.write( "(A)3abc-12ab
\n" ); document.write( "(B)3abc+12ab
\n" ); document.write( "(C)abc+12ab
\n" ); document.write( "(D)3abc
\n" ); document.write( "please show how to solve this question\r
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document.write( "          a+b+c = 4\r\n" );
document.write( "            a+b = 4-c\r\n" );
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document.write( "Cube both sides:\r\n" );
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document.write( "         (a+b)³ = (4-c)³\r\n" );
document.write( "a³+3a²b+3ab²+b³ = 64-48c+12c²-c³\r\n" );
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document.write( "We want to find a³+b³+c³-12c²+48c-64,\r\n" );
document.write( "so we isolate that expression on the left\r\n" );
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document.write( "a³+b³+c³-12c²+48c-64 = -3a²b-3ab² = \r\n" );
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document.write( "-3ab(b+a) = -3ab(a+b) = -3ab(4-c) = \r\n" );
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document.write( "-12ab+3abc = 3abc-12ab\r\n" );
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document.write( "So the correct choice is (a). \r\n" );
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document.write( "Edwin
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