document.write( "Question 1037399: If x-y=4 and xy=21 find x^3-y^3 \n" ); document.write( "

Algebra.Com's Answer #652050 by ikleyn(52787) $\"\"$ $\"About$

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\n" ); document.write( "If x-y=4 and xy=21 find x^3-y^3
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document.write( " =    (which is classic identity)\r\n" );
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document.write( "=    (now plug-in the given data)\r\n" );
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document.write( "= 4*(4^2 +3*21) = 4*(16+63) = 4*79 = 316.\r\n" );
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