document.write( "Question 1041231: Find x if the sequence m,x,n is an arithmetic
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Algebra.Com's Answer #656207 by ikleyn(52792) $\"\"$ $\"About$

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\n" ); document.write( "Find x if the sequence m,x,n is an arithmetic
\n" ); document.write( "Please help and explain how to
\n" ); document.write( "Thank you in advance :)
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document.write( "If three numbers a, b and c form an arithmetic progression, then the middle number is half-sum of the two others:\r\n" );
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document.write( "b = .\r\n" );
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document.write( "Indeed, b = a+d and c = a+2d, then a + c = (a + a+2d) = 2a + 2d.\r\n" );
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document.write( "Hence,  =  = a + d =b.\r\n" );
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document.write( "Therefore, in your case, x = .\r\n" );
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\n" ); document.write( "\n" ); document.write( "See the lesson One characteristic property of arithmetic progressions in this site.\r
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