document.write( "Question 1129675: Prove that the value of the expression is not divisible by 6 for any whole n:
\n" ); document.write( "(2n+1)(n+5)–2(n+3)–(5n+13).
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Algebra.Com's Answer #746263 by MathLover1(20849)\"\" \"About 
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\n" ); document.write( "\"%282n%2B1%29%28n%2B5%29+-2%28n%2B3%29+-+%285n%2B13%29\"\r
\n" ); document.write( "\n" ); document.write( "Hint: an integer is divisible by \"6+\"if and only if it is divisible by both \"2\" and \"3\". \r
\n" ); document.write( "\n" ); document.write( "Can you show that your expression is even,divisible by both \"2\" and \"3\" ? \r
\n" ); document.write( "\n" ); document.write( "first simplify it:\r
\n" ); document.write( "\n" ); document.write( "\"%282n%2B1%29%28n%2B5%29+-2%28n%2B3%29+-+%285n%2B13%29\"\r
\n" ); document.write( "\n" ); document.write( "\"2n%5E2%2B10n%2Bn%2B5+-2n+-6+-+5n-13\"\r
\n" ); document.write( "\n" ); document.write( "\"2n%5E2%2B11n+%2B5+-7n+-6+-13\"\r
\n" ); document.write( "\n" ); document.write( "\"2n%5E2+%2B4n%2B5-19\"\r
\n" ); document.write( "\n" ); document.write( "\"2+n%5E2+%2B+4+n+-+14\"\r
\n" ); document.write( "\n" ); document.write( "\"2+%28n%5E2+%2B+2+n+-+7%29\" => GFC is \"2\"; \r
\n" ); document.write( "\n" ); document.write( "so,it is divisible by \"2\", \r
\n" ); document.write( "\n" ); document.write( "but it is \"not\" divisible by \"3\"\r
\n" ); document.write( "\n" ); document.write( "=>consequently, it is \"not\" divisible by \"6\" either
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