document.write( "Question 1086736: the first and the last terms of an arithmetic series are 25 and 197. find the sum of 10th term of the series\r
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Algebra.Com's Answer #700953 by MathTherapy(10552)\"\" \"About 
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the first and the last terms of an arithmetic series are 25 and 197. find the sum of 10th term of the series
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\"S%5Bn%5D+=+%28n%2F2%29%28a%5B1%5D+%2B+a%5Bn%5D%29\" ------- Formula for the sum of an AP\r\n" );
document.write( "\"S%5B10%5D+=+%2810%2F2%29%2825+%2B+197%29\" ----- Substituting 10 for n, 25 for a1, and 197 for an\r\n" );
document.write( "Sum of the 1st 10 terms, or: \r\n" );
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document.write( "OR\r\n" );
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document.write( "1st term, or a1 = 25\r\n" );
document.write( "Last term, or an = 197\r\n" );
document.write( "an = a1 + (n - 1)d\r\n" );
document.write( "an = 25 + dn – d\r\n" );
document.write( "197 = 25 + dn – d ------ Substituting 197 for an\r\n" );
document.write( "172 = dn – d ------ eq (i)\r\n" );
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document.write( "\"S%5Bn%5D+=+%28n%2F2%29%282a%5B1%5D+%2B+%28n+-+1%29d%29\" ------ Formula for the sum of an AP\r\n" );
document.write( "\"S%5B10%5D+=+%2810%2F2%29%282%2825%29+%2B+dn+-+d%29\" ----- Substituting 10 for n, and 25 for a1\r\n" );
document.write( "\"S%5B10%5D+=+5%2850+%2B+dn+-+d%29\"\r\n" );
document.write( "\"S%5B10%5D+=+5%2850+%2B+172%29\" ------ Substituting 172 for dn – 5\r\n" );
document.write( "Sum of the 1st 10 terms, or:
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