document.write( "Question 976741: pleas, solve me \r
\n" ); document.write( "\n" ); document.write( "1) if nP5=6720 find n\r
\n" ); document.write( "\n" ); document.write( "2) solve equation for n
\n" ); document.write( " nP3=210
\n" ); document.write( "thank you for your helping us
\n" ); document.write( "

Algebra.Com's Answer #599492 by Edwin McCravy(20054)\"\" \"About 
You can put this solution on YOUR website!
1) if nP5=6720 find n
\n" ); document.write( "
\r\n" );
document.write( "\"nP5\"\"%22%22=%22%22\"\"n%28n-1%29%28n-2%29%28n-3%29%28n-4%29\"\"%22%22=%22%22\"\"6720\"\r\n" );
document.write( "\r\n" );
document.write( "\"n%28n-1%29%28n-2%29%28n-3%29%28n-4%29\"\"%22%22=%22%22\"\"6720\"\r\n" );
document.write( "\r\n" );
document.write( "Those 5 factors on the left average to the middle one n-2, \r\n" );
document.write( "so the left side isn't far from \"n-2%29%5E5\"\r\n" );
document.write( "\r\n" );
document.write( "So the solution to\r\n" );
document.write( "\r\n" );
document.write( "\"%28n-2%29%5E5\"\"%22%22=%22%22\"\"6720\" \r\n" );
document.write( "\r\n" );
document.write( "should be close to the correct answer,\r\n" );
document.write( "\r\n" );
document.write( "\"n-2\"\"%22%22=%22%22\"\"root%285%2C6720%29\"\r\n" );
document.write( "\r\n" );
document.write( "\"n-2\"\"%22%22=%22%22\"\"5.827386917\"\r\n" );
document.write( "\r\n" );
document.write( "\"n\"\"%22%22=%22%22\"\"7.827386917\"\r\n" );
document.write( "\r\n" );
document.write( "So we try 8\r\n" );
document.write( "\r\n" );
document.write( "\"n%28n-1%29%28n-2%29%28n-3%29%28n-4%29\"\"%22%22=%22%22\"\"6720\"\r\n" );
document.write( "\"8%288-1%29%288-2%29%288-3%29%288-4%29\"\"%22%22=%22%22\"\"6720\"\r\n" );
document.write( "\"8%287%29%286%29%285%29%284%29\"\"%22%22=%22%22\"\"6720\"\r\n" );
document.write( "\"6720\"\"%22%22=%22%22\"\"6720\"\r\n" );
document.write( "\r\n" );
document.write( "n = 8\r\n" );
document.write( "---------------------\r\n" );
document.write( "

\n" ); document.write( "2) solve equation for n
\n" ); document.write( " nP3=210
\n" ); document.write( "
\r\n" );
document.write( "\"nP3\"\"%22%22=%22%22\"\"n%28n-1%29%28n-2%29\"\r\n" );
document.write( "\r\n" );
document.write( "\"n%28n-1%29%28n-2%29\"\"%22%22=%22%22\"\"210\"\r\n" );
document.write( "\r\n" );
document.write( "These 3 factors on the left average to the middle one n-1, \r\n" );
document.write( "so the left side isn't far from \"n-1%29%5E3\"\r\n" );
document.write( "\r\n" );
document.write( "So the solution to\r\n" );
document.write( "\r\n" );
document.write( "\"%28n-1%29%5E3\"\"%22%22=%22%22\"\"210\" \r\n" );
document.write( "\r\n" );
document.write( "should be close to the correct answer,\r\n" );
document.write( "\r\n" );
document.write( "\"n-1\"\"%22%22=%22%22\"\"root%283%2C210%29\"\r\n" );
document.write( "\r\n" );
document.write( "\"n-1\"\"%22%22=%22%22\"\"5.943921953\"\r\n" );
document.write( "\r\n" );
document.write( "\"n\"\"%22%22=%22%22\"\"6.943921953\"\r\n" );
document.write( "\r\n" );
document.write( "So we try 7\r\n" );
document.write( "\r\n" );
document.write( "\"n%28n-1%29%28n-2%29\"\"%22%22=%22%22\"\"210\"\r\n" );
document.write( "\"7%287-1%29%287-2%29\"\"%22%22=%22%22\"\"210\"\r\n" );
document.write( "\"%287%29%286%29%285%29\"\"%22%22=%22%22\"\"210\"\r\n" );
document.write( "\"210\"\"%22%22=%22%22\"\"210\"\r\n" );
document.write( "\r\n" );
document.write( "n = 7\r\n" );
document.write( "\r\n" );
document.write( "Edwin
\n" ); document.write( "
\n" );