document.write( "Question 187236: find what x is so that 3x-1, 5x-4 and 2x+8 are consecutive terms of an arithmetic sequence. \n" ); document.write( "
Algebra.Com's Answer #140347 by jim_thompson5910(35256)\"\" \"About 
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An arithmetic sequence is of the form: a, a+d, a+2d, a+3d, ..., a+nd\r
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\n" ); document.write( "\n" ); document.write( "Note: I'm just adding a constant number to 'a' each time.\r
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\n" ); document.write( "\n" ); document.write( "So if you subtract the 1st term from the second, you get: \"%28a%2Bd%29-a=a-a%2Bd=d\"\r
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\n" ); document.write( "\n" ); document.write( "If you subtract the 2nd term from the 3rd term, you get: \"%28a%2B2d%29-%28a%2Bd%29=%28a-a%29%2B%282d-d%29=d\"\r
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\n" ); document.write( "\n" ); document.write( "If you subtract the 3rd term from the 4th term, you get: \"%28a%2B3d%29-%28a%2B2d%29=%28a-a%29%2B%283d-2d%29=d\"\r
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\n" ); document.write( "\n" ); document.write( "So if you subtract ANY term from the next term, you will ALWAYS get the result of \"d\"\r
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\n" ); document.write( "\n" ); document.write( "In other words, each term is separated by the same distance. \r
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\n" ); document.write( "\n" ); document.write( "In our case, the first term is 3x-1, the second term is 5x-4 and the third term is 2x+8\r
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\n" ); document.write( "\n" ); document.write( "So according to the logic above, this should be true (if the sequence is an arithmetic one):\r
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\n" ); document.write( "\n" ); document.write( "2nd term - 1st term = 3rd term - 2nd term\r
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\n" ); document.write( "\n" ); document.write( "which looks like:\r
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\n" ); document.write( "\n" ); document.write( "\"%285x-4%29-%283x-1%29=%282x%2B8%29-%285x-4%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%285x-4%29-%283x-1%29=%282x%2B8%29-%285x-4%29\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "\"5x-4-3x%2B1=2x%2B8-5x%2B4\" Distribute.\r
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\n" ); document.write( "\n" ); document.write( "\"2x-3=2x%2B8-5x%2B4\" Combine like terms on the left side.\r
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\n" ); document.write( "\n" ); document.write( "\"2x-3=-3x%2B12\" Combine like terms on the right side.\r
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\n" ); document.write( "\n" ); document.write( "\"2x=-3x%2B12%2B3\" Add \"3\" to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"2x%2B3x=12%2B3\" Add \"3x\" to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"5x=12%2B3\" Combine like terms on the left side.\r
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\n" ); document.write( "\n" ); document.write( "\"5x=15\" Combine like terms on the right side.\r
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\n" ); document.write( "\n" ); document.write( "\"x=%2815%29%2F%285%29\" Divide both sides by \"5\" to isolate \"x\".\r
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\n" ); document.write( "\n" ); document.write( "\"x=3\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "Answer:\r
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\n" ); document.write( "\n" ); document.write( "So the answer is \"x=3\"\r
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