document.write( "Question 285284: Explain how you would find the sum of the first 50 even numbers.What is the sum? \n" ); document.write( "

Algebra.Com's Answer #206825 by Edwin McCravy(20056) $\"\"$ $\"About$

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document.write( "Either of two ways:\r\n" );
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document.write( "Let the sum be S. Then write these two equivalent equations\r\n" );
document.write( "and add them:\r\n" );
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document.write( " S =   2 +   4 +   6 +   8 +  10 + ''' +  92 +  94 +  96 +  98 + 100  \r\n" );
document.write( " S = 100 +  98 +  96 +  94 +  92 + ''' +  10 +   8 +   6 +   4 +   2\r\n" );
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document.write( "2S = 102 + 102 + 102 + 102 + 102 + ''' + 102 + 102 + 102 + 102 + 102 \r\n" );
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document.write( "There are 50 terms on the right, so the right side is 50*102 \r\n" );
document.write( "or 2550, so:\r\n" );
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document.write( "2S = 5100\r\n" );
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document.write( "Divide both sides by 2:\r\n" );
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document.write( " S = 2550.  \r\n" );
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document.write( "The other way:\r\n" );
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document.write( "Or, you could use the formula for the sum of an arithmetic\r\n" );
document.write( "series:\r\n" );
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document.write( "Edwin

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