General term from sum formula

If the sum of the first $n$ terms of an arithmetic progression is $2 n + 3 n^{2}$ , find the $r^{th}$ term.

~4 minAnswer checked instantlysum formulageneral term

H. S. Hall & S. R. Knight, Higher Algebra (1891) · Ch. IV. Arithmetical Progression, Examples IV.b, No. 17

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