document.write( "Question 1118102: The sum of the first ten terms of a linear sequence is -60 and the sum of the first fifteen terms of the sequence
\n" ); document.write( "is -165. Find the 18th term of the sequence. \n" ); document.write( "
Algebra.Com's Answer #733369 by ikleyn(52835)\"\" \"About 
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The sum of the first ten terms of a linear sequence is -60 and the sum of the first fifteen terms of the sequence is -165 find the 18th term of the sequence.
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\n" ); document.write( "\n" ); document.write( "        The solution by @stanbon contained errors.
\n" ); document.write( "        I fixed the errors and put the rectified solution below.\r
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\n" ); document.write( "\n" ); document.write( "10(a(1)+a(10))/2 = -60
\n" ); document.write( "15(a(1)+a(15))/2 = -165
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\n" ); document.write( "a(1)+a(10) = -12
\n" ); document.write( "a(1)+a(15) = -22
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\n" ); document.write( "a(10)-a(15) = 10
\n" ); document.write( "-5d = 10
\n" ); document.write( "d = -2
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\n" ); document.write( "a(1) + a(10) = -12
\n" ); document.write( "a(1) + (a(1) + 9d) = -12
\n" ); document.write( "2a(1) - 18 = -12
\n" ); document.write( "2a(1) = 6
\n" ); document.write( "a(1) = 3
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\n" ); document.write( "Ans:: a(18) = 3 + 17*(-2) = 3 - 34 = -31.\r
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