document.write( "Question 552544: I need some help with some homework. I'm struggling with these four problems:
\n" ); document.write( "1. What is the twenty-fifth term of the arithmetic sequence with a1 = –1 and d = –10?
\n" ); document.write( "2.What is the twenty-ninth term of arithmetic sequence with a1 = 13 and d = –5/2?
\n" ); document.write( "3. What are the two arithmetic means between –13 and 8?
\n" ); document.write( "4. What is Sn for the arithmetic series with d = –4, an = 27, and n = 9?
\n" ); document.write( "Thanks so much! \n" ); document.write( "
Algebra.Com's Answer #360394 by AnlytcPhil(1806)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "1. What is the twenty-fifth term of the arithmetic sequence with a1 = –1 and d = –10? \r\n" );
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document.write( "Substitute a1=-1, d=-10, and n=25 in\r\n" );
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document.write( "an = a1 + (n-1)d\r\n" );
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document.write( "Answer: -241 \r\n" );
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document.write( "2.What is the twenty-ninth term of arithmetic sequence with a1 = 13 and d = –5/2? \r\n" );
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document.write( "Substitute a1=13, d=-5/2, and n=29 in\r\n" );
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document.write( "an = a1 + (n-1)d\r\n" );
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document.write( "Answer: -57 \r\n" );
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document.write( "3. What are the two arithmetic means between –13 and 8? \r\n" );
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document.write( "a1 - -13, a2 = ?, a3 = ?, a4 = 8\r\n" );
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document.write( "Each term differs from the preceding term by d.\r\n" );
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document.write( "a2 is a1 + d, and a3 is a4 - d, so\r\n" );
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document.write( "a1 = -13, a2 = -13+d, a3 = 8-d, a4 = 8\r\n" );
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document.write( " a2 + d = a3\r\n" );
document.write( "-13+d+d = 8-d\r\n" );
document.write( " -13+2d = 8-d\r\n" );
document.write( "     3d = 21\r\n" );
document.write( "      d = 7\r\n" );
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document.write( " a2 = -13+7 = -6\r\n" );
document.write( " a3 = 8-7 = 1\r\n" );
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document.write( "-13, -6, 1, 8\r\n" );
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document.write( "They are -6 and 1\r\n" );
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document.write( "4. What is Sn for the arithmetic series with d = –4, an = 27, and n = 9? \r\n" );
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document.write( "First substitute an = 27, d=-4, and n=9 in\r\n" );
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document.write( "an = a1 + (n-1)d\r\n" );
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document.write( "and solve for a1.\r\n" );
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document.write( "Get a1 = 59\r\n" );
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document.write( "Substitute a1 = 59, d = -4, leave n as just n in\r\n" );
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document.write( "Sn = (n/2)[a1 + (n-1)d]\r\n" );
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document.write( "Simplify\r\n" );
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document.write( "Get\r\n" );
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document.write( "Sn = n(61-2n)\r\n" );
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document.write( "Edwin
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