document.write( "Question 1070724: If NP2=90 , then find n
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Algebra.Com's Answer #685796 by Edwin McCravy(20056) $\"\"$ $\"About$

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document.write( "NP2 means N(N-1)\r\n" );
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document.write( "N(N-1) = 90\r\n" );
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document.write( "N(N-1) = 90\r\n" );
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document.write( "N(N-1) = 90\r\n" );
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document.write( "N2 - N = 90\r\n" );
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document.write( "N2 - N - 90 = 0\r\n" );
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document.write( "(N-10)(N+9) = 0\r\n" );
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document.write( "N-10=0;  N+9=0\r\n" );
document.write( "   N=10;   N=-9\r\n" );
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document.write( "Ingnore negative answer.\r\n" );
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document.write( "Check:\r\n" );
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document.write( "10P2 = 10(9) = 90\r\n" );
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document.write( "Edwin

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