document.write( "Question 603294: I'm supposed to find the specific term of each arithmetic sequence. The problem is : t1=5, t3=20; and I need to find t subscript 12. I can use the equation tn=t1+(n-1)d if that helps you any? Thanks for the help. \n" ); document.write( "

Algebra.Com's Answer #380660 by htmentor(1343) $\"\"$ $\"About$

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The n-th term of the arithmetic sequence is written t_n = t1 + (n-1)d where
\n" ); document.write( "d = the common difference and t1 is the 1st term
\n" ); document.write( "So we need to find d
\n" ); document.write( "We can form two equations for the common difference
\n" ); document.write( "d = t2 - t1 = t2 - 5
\n" ); document.write( "d = t3 - t2 = 20 - t2
\n" ); document.write( "Add the two equations together:
\n" ); document.write( "2d = 15 -> d = 7.5
\n" ); document.write( "Therefore, t12 = 5 + 7.5(12-1)
\n" ); document.write( "t12 = 87.5 \n" ); document.write( "

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