document.write( "Question 855486: The sixth term of an AP is 37 and the tenth term 53.Find the first term. \n" ); document.write( "
Algebra.Com's Answer #515387 by KMST(5328)\"\" \"About 
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MENTAL MATH (for multiple choice tests):
\n" ); document.write( "from one number to the next you are adding a common difference.
\n" ); document.write( "From the sixth term to the tenth term that common difference was added 4 times because
\n" ); document.write( "\"10-6=4\" .
\n" ); document.write( "That means that the common difference is
\n" ); document.write( "\"%2853-37%29%2F4=16%2F4=4\" .
\n" ); document.write( "From the first term to the sixth term that common difference was added 5 times because
\n" ); document.write( "\"6-1=5\" .
\n" ); document.write( "That means that the common difference (4) was added 5 times, so the first term is
\n" ); document.write( "\"37-5%2A4=37-20=highlight%2817%29\" .
\n" ); document.write( "That is a lot of words, but you can think through the concepts and calculations much faster than you can explain and write them.
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\n" ); document.write( "USING FORMULAS (to please the teacher by \"showing your work\"):
\n" ); document.write( "\"a%5B1%5D\"= first term
\n" ); document.write( "\"d\"= common difference
\n" ); document.write( "\"a%5Bn%5D=a%5B1%5D%2B%28n-1%29%2Ad\"= general formula for term number \"n\".
\n" ); document.write( "For \"n=6\" we know that
\n" ); document.write( "\"a%5B6%5D=a%5B1%5D%2B%286-1%29%2Ad=a%5B1%5D%2B5%2Ad=37\"
\n" ); document.write( "For \"n=10\" we know that
\n" ); document.write( "\"a%5B10%5D=a%5B1%5D%2B%2810-1%29%2Ad=a%5B1%5D%2B9%2Ad=53\"
\n" ); document.write( "\"system%28a%5B1%5D%2B5%2Ad=37%2Ca%5B1%5D%2B9%2Ad=53%29\" is solved to get \"system%28highlight%28a%5B1%5D=17%29%2Cd=4%29\"
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