document.write( "Question 1045000: Two elements of a sequence are 3 and 13.
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Algebra.Com's Answer #660458 by Edwin McCravy(20056)\"\" \"About 
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document.write( "(I) 3, 13, 23, 43, 53, 63, ...\r\n" );
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document.write( "That's the arithmetic sequence that has first term a1=3\r\n" );
document.write( "and common difference d=10.  So we use the formula for the nth\r\n" );
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document.write( "an = a1+(n-1)d\r\n" );
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document.write( "Substituting a1=3, d=10.\r\n" );
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document.write( "The general term is\r\n" );
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document.write( "an = 3+(n-1)(10)\r\n" );
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document.write( "an = 3+10(n-1)\r\n" );
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document.write( "an = 3+10n-10\r\n" );
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document.write( "an = 10n-7    <--general term\r\n" );
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document.write( "Substituting n=25\r\n" );
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document.write( "a25 = 10(25)-7\r\n" );
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document.write( "a25 = 250-7\r\n" );
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document.write( "a25 = 243     <--25th element\r\n" );
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document.write( "-------------------------\r\n" );
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document.write( "(II) 3, 8, 13, 18, 23, 27, ...\r\n" );
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document.write( "That's the arithmetic sequence that has first term a1=3\r\n" );
document.write( "and common difference d=5.  \r\n" );
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document.write( "Do it the same way.\r\n" );
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document.write( "-------------------------\r\n" );
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document.write( "(III) 1, 3, 5, 7, 9, 11, 13, 15, ...\r\n" );
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document.write( "That's the arithmetic sequence that has first term a1=1\r\n" );
document.write( "and common difference d=2.  \r\n" );
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document.write( "Do it the same way.\r\n" );
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document.write( "Edwin
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