document.write( "Question 217318: The third term of an arithmetic sequence is 4 and the sum of the first 8 term is 36. Write down the first 8 term of the sequence.
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Algebra.Com's Answer #163891 by drj(1380)\"\" \"About 
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The third term of an arithmetic sequence is 4 and the sum of the first 8 term is 36. Write down the first 8 term of the sequence. \r
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\n" ); document.write( "\n" ); document.write( "Step 1. An arithmetic sequence goes from one term to the next by always adding (or subtracting) the same value \r
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\n" ); document.write( "\n" ); document.write( "Step 2. Let x be the number to add or subtract in the sequence.\r
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\n" ); document.write( "\n" ); document.write( "Step 3. Let a be the first term, let a+x be the second term, let a+2x be the third term, a+3x be the fourth term, and a+(n-1)x be the nth term\r
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\n" ); document.write( "\n" ); document.write( "Step 4. Let a+7x be the 8th term. Then the sum of the first and eighth term is a+a+7x=2a+7x. The sum of the second term and seventh term is the a+x+a+6x=2a+6x. So four the first eight terms, there will be four pairs of 2a+6x which will equal to 36 or\r
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\n" ); document.write( "\n" ); document.write( "\"4%2A%282a%2B7x%29=36\"\r
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\n" ); document.write( "\n" ); document.write( "\"2a%2B7x=9\" Equation A\r
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\n" ); document.write( "\n" ); document.write( "Also \"a%2B2x=4\" Equation B since the 3th term is 4.\r
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\n" ); document.write( "\n" ); document.write( "Step 5. Then we have a system of equations given as Equations A and B. The following steps will solve the equation by substitution.\r
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Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
\n" ); document.write( " \"+system%28+%0D%0A++++2%5Ca+%2B+7%5Cx+=+9%2C%0D%0A++++1%5Ca+%2B+2%5Cx+=+4+%29%0D%0A++\"We'll use substitution. After moving 7*x to the right, we get:
\n" ); document.write( " \"2%2Aa+=+9+-+7%2Ax\", or \"a+=+9%2F2+-+7%2Ax%2F2\". Substitute that
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\n" ); document.write( " \"1%2A%289%2F2+-+7%2Ax%2F2%29+%2B+2%5Cx+=+4\" and simplify: So, we know that x=0.333333333333333. Since \"a+=+9%2F2+-+7%2Ax%2F2\", a=3.33333333333333.
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\n" ); document.write( " Answer: \"system%28+a=3.33333333333333%2C+x=0.333333333333333+%29\".
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\n" ); document.write( "\n" ); document.write( "So a=\"10%2F3\" and x=\"1%2F3\"\r
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\n" ); document.write( "\n" ); document.write( "So sequence is: \"10%2F3\", \"11%2F3\", \"4\", \"13%2F3\", \"14%2F3\", \"5\", \"16%2F3\", \"17%2F3\".\r
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\n" ); document.write( "\n" ); document.write( "Check: The third term is \"4\" and the sum is \"%2810%2B11%2B12%2B13%2B14%2B15%2B16%2B17%29%2F3=36\" \r
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\n" ); document.write( "\n" ); document.write( "Step 6. ANSWER: The sequence is \"10%2F3\", \"11%2F3\", \"4\", \"13%2F3\", \"14%2F3\", \"5\", \"16%2F3\", \"17%2F3\".\r
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\n" ); document.write( "\n" ); document.write( "I hope the above steps and explanation were helpful. \r
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\n" ); document.write( "\n" ); document.write( "For Step-By-Step videos on Introduction to Algebra, \r
\n" ); document.write( "\n" ); document.write( "please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra and \r
\n" ); document.write( "\n" ); document.write( "for Trigonometry please visit \r
\n" ); document.write( "\n" ); document.write( "http://www.FreedomUniversity.TV/courses/Trigonometry. \r
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\n" ); document.write( "\n" ); document.write( "Also, good luck in your studies and contact me at \r
\n" ); document.write( "\n" ); document.write( "john@e-liteworks.com for your future math needs.\r
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\n" ); document.write( "\n" ); document.write( "Respectfully,
\n" ); document.write( "Dr J\r
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