document.write( "Question 1172506: the 7th term of an ap is 17 and the13th term is 12 more than the 7th term find the sum of the first 18th terms of the ap \n" ); document.write( "

Algebra.Com's Answer #797561 by Boreal(15235) $\"\"$ $\"About$

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This was shown earlier to have a1=5 and d=2 from an=a1+d(n-1)
\n" ); document.write( "Sum is (n/2)(2a+(n-1)d)
\n" ); document.write( "=(18/2)(10+2*17)=9*44=396
\n" ); document.write( "the terms are
\n" ); document.write( "5
\n" ); document.write( "7
\n" ); document.write( "9
\n" ); document.write( "11
\n" ); document.write( "13
\n" ); document.write( "15
\n" ); document.write( "17
\n" ); document.write( "19
\n" ); document.write( "21
\n" ); document.write( "23
\n" ); document.write( "25
\n" ); document.write( "27
\n" ); document.write( "29
\n" ); document.write( "31
\n" ); document.write( "33
\n" ); document.write( "35
\n" ); document.write( "37
\n" ); document.write( "39
\n" ); document.write( "and add to 396. \n" ); document.write( "

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